Of interactive applications, and excluding any special-purpose apps I use for work whose names won't ring any bells:

1. FireFox
2. TextPad
3. TotalCommander (I have a regular love affair with this one!)
4. TheBat!
5. KeyNote

Honorary mentions: locate32, Reget Deluxe, Archivarius (I couldn't see why one would buy a desktop search app with so many available for free, then I realized Archivarius supports TheBat and Forte Agent databases. A lifesaver.)

But then there are non-interactive tools that run constantly in the background and make the whole environment livable. I tend to forget about those until it's reinstall time ev ery few years and I find some things are missing. Here's to those silent, trusty utilities!

1. KatMouse (the functionality used to be present in Logitech drivers, then they removed it)
2. HoeKey (I replaced it with AutoHotkey only recently, but HoeKey served me well for a very long time)
3. FileEx (never want to see the unenhanced File Open dialog again!)
4. Backup4All
5. URLInject (a program I wrote to insert page URL, title and date/time in every html file saved from a browser)

Honorary mentions, I guess: svchost.exe, winlogon.exe, csrss.exe, spoolsv.exe, System Idle Process

FullRecall

looks interesting...

FullRecall is a software that can help you memorize the knowledge for lifelong periods with the minimum time investment. Underlying artificial neural network gradually grasps your forgetting curve to schedule optimal days for the reviews–i.e., days when you will be close to forgetting an information.

http://fullrecall.com/

Firefox
KeePass
Directory Opus
EmEditor
Acemoney

Honorary mention: JungleDisk (runs constantly in the background)

OK let's see, I'd say it'll look something like this:

1. XChat2
2. Pidgin
3. KMail
4. Akregator
5. Firefox

Then again, most of my 'most used applications' are running all the time.
Accounting for this, it should look like this:

1. XChat2, Pidgin, KMail, Akregator, Firefox, Amarok
2. Bibble Pro
3. digiKam
4. Inkscape
5. Open Office

FireFox
Total Commander
Thunderbird
PuTTY
Boxer Text Editor
Total Launchbar*

Since Browsers and Email are always used, I'll add two more:
Irfanview
UltraISO

Can't live with Process Explorer either....

Always running in back:

AlphaClock
ClockX
Daemon Tools
Ghost
TightVNC
EverNote Lite
Process Tamer
Total LaunchBar*

*It's both.. always running and I use it all the time.

Corel Photo-paint
Robo-form
Maxthon
Sync-Notes

[attach]

FireFox
Putty
Mirc
TheBat!
PowerPoint 2007

Total Launchbar*

Do you mean TrueLaunchbar?