TotalCommander (or, I guess, Directory Opus) - the first thing I install on a new system
FARR, obviously! - comes second after TC, only then can I actually run software comfortably.
TrueLaunchBar (can't live without it. I hope it runs under Win7!)
Actual Window Manager (a must for me, but it does so much more than manage windows on multiple monitors)
A text editor is a draw between
EmEditor,
EditPad Pro or
HippoEdit.
Startup Monitor - there are plenty more advanced tools to manage startup items, but this one takes a minuscule amount or memory and prompts you immediately when something gets added to a startup location. Another must early install on a new system, before I start installing much else. For heavy-duty maintenance,
Anvir Task Manager.
Firefox. Chrome is just too emo!
Obviously a media player, but I don't have a favorite (they all suck in various ways). The minimum today would be
Media Player Classic - Homecinema, I guess.
Zoom Player is top of the line, but shamelessly expensive, and not very functional for audio.
J-River Media Center is a fantastic organizer and great audio player, but has a sucky UI for playing video (stay with their freeware MediaJukebox, which only does audio). Winamp is great but s-lo-o-w, and AIMP is great but buggy, so...
Um, KeyNote
Calendarscope - my preferred calendar; wish it had better handling of to-do tasks
Autohotkey, it speeds up my real-life work like no contest.
TheBat! for email. Even with the editor annoynances, it's always been 100% reliable for me, it would take a lot of convincing for me to even try anything else.
Ditto (another work booster),
USB Safely Remove and definitely
KatMouse (lets you scroll a window without clicking/focusing it first. Another invisible app I can't live without.)
Backup4All, consistently the best, and I've tried a lot of alternatives. The day it starts supporting real-time backup it will be perfect.