Computer: Dell. We're not running exclusively Dell here, but any new machines I buy will probably be Dells. Haven't had a moment's trouble with any of 'em.
Video cards: ATI Radeons. I had a rough experience with nVidia OpenGL for an application other than a game, so I've been sticking with ATI ever since. Having a unified driver install so I don't have to remember each card's specs is also a plus. I never install those annoying system-tray add-ons, though. We're all running giant monitors, so a virtual desktop isn't all that useful.
Monitor: Dell 2001FP LCD's. Absolutely beautiful and very well designed. The little snap-on sound bar is great for conserving desk-space, but I wouldn't recommend it for immersive gaming.
Mice: Microsoft optical wheel-mice. Nothing fancy, but they work very well. Haven't had one go bad yet. $15 at Fry's, so the price is right.
Printers: HP inkjets. The ink is expensive, but they do work well with the odd paper we occasionally use (transparent bond, mylar). Only other complaint is that they update models so often that it's hard to standardize your printers on a particular ink cartridge.
Oh, and be sure to return dead ink cartridges to Office Depot and get some free paper. Our plotter can use up a cartridge in ten days on a busy week, so I've got about 50 reams of new paper in the supply closet now :)
OS: Windows XP Pro with service pack 2. Works very well and runs everything we need.
Office Suite: MS Office 2003 Pro. It's very stable and is what just about everyone uses. A couple of clients still use WordPerfect, but Word's WP-importer does the job for those folks. Outlook's new spam filter does a good job. Also, the backward file-compatibility is good, because our clients have all kinds of different versions of stuff.
Backup: EZ-BackItUp. It's a nice little free tool that'll duplicate a directory structure on a remote drive. It only copies over changed files (and removes removed files) after the initial "big copy", so it's very fast. It's got its own scheduler that I use to schedule daily backups of all the machines to a couple of large external drives at about 3 AM, so it's unobtrusive.
ZIP: PowerArchiver. It's very simple to use and has pretty-much every feature I want in a zip tool. It's $10 cheaper than WinZip and supports a lot more archive formats. Also you can make self-exploding zipfiles without paying extra, ala Winzip. Also it comes with a command-line version, which we use for. . .
CD-burning: Nero. We've got a late-night batch file that runs the PowerArchiver command-line version and zips up the daily backups on our file-person's machine. She then burns the daily zips on a DVD so we've got a good archive of drawings. Nero's dirt-simple to use and works perfectly despite the fact that we've got about 7 different CD/DVD burners in here. We just use the $5 oem version, as we don't have much use for all the extra toys you get with the full product (video and sound editor, DVD player, etc).
Imaging: Paint Shop Pro. It's got damn near as many features as Photoshop for about 1/4 the price. It's handy for the occasional time that we need to stitch together several bitmap files.
Media playing: Windows Media Player 10, Quicktime Alternative and Real Alternative. That pretty-much covers every media type that we can download and play, and none of 'em are eager to fill your screen with popups and politely wait in memory even when you're not playing something. I've made it clear that anyone installing the full Quicktime or RealPlayer is in trouble :)
Utilities: v-com SystemSuite 5. This is the only utility suite I've found that doesn't do lots of annoying stuff to your system, making it less stable with the aim of making your system more stable. Other than a system tray icon that checks email for virii, I wouldn't know it was there. It's not perfect, though. The disk defragmenter, for one, has a long-standing bug where it chokes on longass filenames full of odd characters (like you'll find in your cookies-folder). In its favor, though, is the fact that it's never asked me to pay for virus-updates, despite the fact that it downloads new virus definitions at least twice a week.
Text Editor: UltraEdit 5. Yeah, this is about six versions outta date, but I stick with it because it was a freebie in one of those British computer magazines with the DVD full of registered "last year's version" shareware. It does everything I need, including hex editing and word-wrap for readme files. If I ever needed to replace it, though, I'd probably go with one of the multitude of free good editors out there. The author used to creep me out a bit because his site was full of religious zealoutry, but he appears to have toned it down quite a lot, reducing it to a single story about how God told him to sell a shareware text editor. To each his own, I guess.
That's my list for now. I'd add the (now discontinued, but still superior) Microsoft Natural Keyboard Pro to the list, but a couple of our folks have near-religious dislike for curved keyboards, so our keyboards are a mix of MS keyboards and those cheap ones that come with the computer :)
Oh, and something else. My wife discovered http://www.booksforsoldiers.com/, which is a site where soldiers can request books for donation. We had an old copy of Stephen King's "Wolves of the Calla" that somebody wanted, so we sent it along. There are some requests for C programming books, so if you've got some extra books sitting around, you can send 'em to a good cause. Since they're going to an APO, it's not expensive to send a book to Iraq.