Firefox
PowerISO
CCleaner

visual studio 2008 C# and asp.net.
Firefox
winamp

Illustrator CS3 - man, I can't get enough of vector graphics!
Photoshop CS3
Quicktime and VLC - depending of the codecs ^^
and well, I try to avoid as possible MS apps... It's just that... how to say that?... I hate badly-written, obscure ergonomy, and "I-use-as-many-ressources-as-possible-on-your-computer-even-if-my-job-consists-only-of-treating-text-and-numbe rs" apps... :p

1. iTunes - Music is second to none and tied with games as most consumed medium.
2. Abiword - I write. Alot.
3. winRAR.

Yes, it can. Skip the boring stuff and list the ones that are interesting. Otherwise it will always be a browser, an email client and office package of some kind.

Lately I have been working on Labview quite a lot for research, we use it to control all the parts of our vehicle and record the data. And I have a feeling that MAESTRO is going to start playing a big part of my life the next couple of months, it is a prorgram used to design ships and determine the stresses applied on it and all that fun stuff. I have used Matlab a fair amount in the past, and it is a truly powerful program if you know what you're doing with it.

If I disregard Firefox which houses most of my essential activities through plugins (google reader notifier, gmail notifier, ftp client, irc client - chatzilla) the 3 most used apps are:
1. Y!IM - pretty obvious, Yahoo! Instant Messenger as most of my friends are on Y! and now it works with people from MSN as well;
2. TweetDeck - Air Twitter client; very useful because it allows sorting of tweets based on the person who sent them and allows multiple groups. I use Twitter a lot to keep in touch with people (recently more than IM).
3. Rainlendar premium - it integrates with my Google Calendar (I use Google apps a lot) and syncs both ways so if I add an event in Rainlendar it appears in GCal and the other way around; this coupled with SMS alerts from GCal makes it the best thing ever!

Hmm, I suppose I should discount startup things that run in the background because those are a given.
Most used non-game, non-browser programs:
Foobar - I prefer this music player. Does what I need it to do with no BS, has some plugins I like.
Notepad - Yep.
GIMP - Free, fun to make chessy image macros.
HOWEVER, the two startup programs I mentioned, for those interested are:
Switcher - One under-explored feature of Vista is Desktop Window Manager, which has a very flexible and public API for devs to play with. Switcher is a Expose clone that lets me quickly view all my open windows at once. Couldn't live without it.
HUD.Vision skin because it's very unintrusive and minimalistic

WeGame, iTunes, and Raptr.

Firefox, Corel Paint Shop Pro X and Macromedia Dreamweaver 8 as I'm constantly working on some websites.

Doubled, in no particular order:
Firefox
Mediamonkey
Notepad
7-Zip
Steam
DosBox
At work:
Firefox
Remote Desktop
Command Line
Notepad
Outlook 2003
Word
Excel
Active Directory... thingy. Haven't really noticed the title on this one.
Group Policy Object Editor

1. Internet Explorerator
1a. Porn, no, wait, er... I mean... Porn... ah shit...
2. Visual Studio
3. Outlook

1. Notepad (kinda surprised me...then again, I play a lot of strategy games whose user-made campaign/scenario readme's are all .txt files)
2. WinAmp
3. VLC Player

Photoshop, mediamonkey, and flash... i was gonna make separate lists for work/home, but realized they were the same >_<

firefox,rapid uploader,flock