No, you don't really need to pay too much attention to an application's hard drive footprint any more. After all, when you can buy a 1.5Tb drive for less than $150US, what difference does a few megs here or there make?
On the other hand, it's amazing to see what some developers are able to accomplish with a very small amount of code.
There are a ton of great, free applications that have been created in less than 1Mb - I didn't fully realize just how many until I started putting this list together. This is by no means a complete list, so if your favorite got overlooked make sure to share it in the comments!
Launchy (408Kb) - Hotkeys FTW! Launchy does more than hotkeys, of course, but even if you add a bucketload of plugins it's still under 1Mb.
Open++ (114Kb) - Helps you tweak your context menu six ways from Sunday. Pair it with another app like NirCmd for a nice one-two punch.
ViGlance (198Kb) - Want Windows 7's iconized taskbar in XP or Vista? ViGlance pulls it off in just under 200Kb. It also swaps the start button for the orb (on XP, of course) and does program grouping and pop-up window lists.
VirtuaWin (385Kb) - Most Linux distributions enable multiple virtual desktops by default. Windows doesn't support them out of the box - so you'll need an app like VirtuaWin. It's a good way to keep your workspace organized.
XNeat (797Kb) - No need to bother with separate apps to shuffle your taskbar icons, roll up windows, or add transparency. XNeat does it all in a single, tiny package. Also allows you to hide windows, minimize to tray, create keyboard shortcuts, and a whole lot more.
DiskCryptor (740Kb) - One thing TrueCrypt can do that OmZiff can't is encrypt volumes. DiskCryptor can do it, too, and it's well under the 1Mb mark
LockNote (320Kb) - If the only thing you really want to encrypt are some private thoughts and notes, Steganos' GPL LockNote is a good choice.
OmZiff (408Kb) - Protecting sensitive data with encryption is never a bad idea. While OmZiff doesn't have the massive featureset of TrueCrypt, it's one-tenth the size and provides all the essential functions and includes a file shredder and password generator.
7-Zip (919Kb) - Sure, 7-zip's main application window is ugly, but who uses it? All the archiving and extracting power you need is just a right-click away.
Everything (334Kb) - A great desktop search tool, Everything indexes your drive contents quicky and supports find-as-you-type. There's a portable version available as well, and it's even smaller.
FastCopy (194Kb) - Both FastCopy and TeraCopy are great, free apps that make copying and moving large amounts of data easier. For me, FastCopy wins because it's free for commercial use, Open Source, and about one quarter the size of TeraCopy.
Fling (230Kb) - Those cheap hard drives make an excellent place to back up and archive your files. Fling not only handles drive-to-drive sync, but it also plays well with FTP servers and USB flash drives. It's one of my favorite discoveries this year.
QDir (439Kb) - If you can get used to the multi-pane crazines, QDir is an awesome tool for manually managing your files and folders.
Space Sniffer (863Kb) - CCleaner does a great job of removing crap from your system, but sometimes you need to dig a little deeper. Space Sniffer helps you locate unwanted space hogs graphically.
Suction (180Kb) - One great way to keep mess to a minimum on your system is to consolidate similar directories - that's exactly what Suction does. It's portable, too!
WinCD Emu (783Kb) - Daemon Tools and Virtual CloneDrive are more well-known programs for mounting ISO images as virtual optical drives in Windows, but WinCD Emu provides almost the same functionality in a smaller package. It handles ISO, IMG, CUE, BIN, and RAW files.
Internet and Networking
Ammyy Admin (548Kb) - While it lacks TeamViewer's speed and bonus features, Ammyy still provides firewall-friendly remote control. There are no ports to open, and if trust is an issue you can run your own Ammyy router (85Kb) instead of using theirs.
GMail Notifier Plus (985Kb) - With kicked-up support for Windows 7's jumplists, this is a useful, sexy helper app for anyone with a GMail account.
Hamachi (989Kb) - Even though it's about 50% bigger than it used to be, Hamachi is still pretty dang small - and very useful. Its zero-config VPN makes remote access to your systems a breeze.
HydraIRC (949Kb) - The installer pushes HydraIRC over 1MB, but the portable version squeaks in under the wire. Features a tabbed interface, skin support, DCC chat and transfers, channel monitoring, and loads more.
iFTP (838Kb) - I love the second line from the developer's site: " I originally wrote i.Ftp to be the first freeware graphical client for BeOS, but someone beat me to it by a few days and well nobody notices who comes 2nd." That might be true, but he still put together a very capable FTP client with SFTP support.
NewsSifter (262Kb) - An intelligent RSS feed reader that analyzes new items based on content and sorts them into categories that you create.
Putty (444Kb) - Classic SSH/terminal client. 'Nuf said.
uTorrent (270Kb) - I've been using uTorrent as long as I've been downloading torrent files. It's got all the features I need in a client (and more) and it's well under the 1Mb mark even if you add the WebUI zip file. Sure, there are other options, but uTorrent takes it easy on my system resources and just gets the job done.
Wakoopa (309Kb) - A fun (and informative) social app, Wakoopa tracks your application usage and lets you see what programs other users are running. It's a great way to discover apps you may not have tried before.
Evil Player (537Kb) - A lightweight, minimal audio player, Evil Player support all the major formats and streams Icecast and Shoutcast (which can be recorded as well).
Fotografix (370Kb) - This little gem has generated quite a bit of buzz since I first wrote it up. It's an excellent lightweight Photoshop alternative, with features like layers, masks, filters, scripts, and editable type. If the developer's site is down, grab the file from Rapidspread.
Greenshot (160Kb) - An open source screen capture tool, Greenshot supports full screen, window, and selection captures, saving to multiple image formats, and annotations. Both a portable version and installer (404Kb) are available.
iDump (197Kb) - Need a free, portable app to backup the contents of an iPod? iDump is a good tool for the job, and it downloads in a flash - even on dial-up.
NCH Express Burn (390Kb) - ImgBurn is my default Windows burning application, but Express Burn sports a lot of the same features and packs them into a much smaller package.
VideoCacheView (65Kb) - It's hard to pick a single NirSoft app to list, because so many of Nir's utilities are under 1Mb and they're all handy. This one scours your browsers' cache files for FLVs and SWFs and allows you to save them for offline viewing.
Office and Productivity
ArsClip (986Kb) - A better clipboard manager with tons of configuration options and features. It's packaged as a zip and totally portable.
CintaNotes (365Kb) - drop it on your Flash drive, and CintaNotes provides an excellent way to collect snippets, links, and any other text data. It supports tagging and search-as-you-type.
Converber (253Kb) - Its unit-conversion super powers are tought to beat. You might not use Converber often, but it's small enough to keep around just in case.
KA TypeIn (920Kb) - A fantastic little app that lets you easily create and reuse text snippets. You can get advanced with it as well since it supports variables. Also does autocompletion.
List² (32kb) - You certainly don't need Excel to create very basic spreadsheet-style lists. This app is more than capable, and it takes up about as much space on your drive as the first page of Excel's help file.
NCS Personal Finance (424Kb) - A nice, simple program to create and track your household budget. Supports multiple budgets as well, so you can use it to keep tabs on the whole family on an individual basis.
TinyPDF (586Kb) - Just north of half a meg, and able to create good quality PDFs from any application via file > print. No longer freeware, but you can grab the last free installer from Freeware Files.
TinySpell (590kb) - Not all our favorite apps include a spellchecker. TinySpell fills the gaps and boasts a 110,00 word dictionary.
WinWorkBar (593Kb) - A productivity-boosting calendar and todo list / GTD application rolled into a sidebar (that can be set to autohide).
Utilities and Maintenance
CCleaner (979Kb) - One of the best file and registry cleanup tools around, and the portable version still still weighs in under 1Mb.
FileHippo Update Checker (154Kb) - FileHippo is a great place to download popular free applications. It's not cluttered with deceptive ads and the site is well-organized. The Updater is a smart way to keep your installers up-to-date.
HijackThis (793Kb) - A must-have for malware cleanup. I don't recommend HJT to casual users, but if you're a DIY-er with a good idea what should and shouldn't be in your registry, it belongs in your toolkit.
Magical Jellybean Keyfinder (367Kb) - Before you reformat your system it's a good idea to back up the product keys for your installed programs. Jellybean is a free, Open Source app that quickly digs up your keys and saves them to a TXT or CSV file.
NirCmd (86Kb) - I tried, but deep down I knew I couldn't get through this list without a second NirSoft app. NirCmd packs a ton of command-line Kung Fu in a single download.
Process Lasso (544Kb) - Gives you better control over the processes running on your system. If you're typically using loads of applications at once, Process Lasso can help keep your system running smoothly. Tweak things manually, or let ProBalance do the work for you.
UltraDefrag (374Kb) - A good defrag tool helps keep your hard drive running like clockwork. Under half a meg and open source, UltraDefrag even comes in 64-bit flavors and there's a micro build (as if 374Kb wasn't small enough already).
Unlocker (252Kb) - I hate trying to delete a file only to have Windows notify me that I can't because the file is in use. Unlocker provides a simple remedy to that problem.