Nobody mentioned
Opera so far, I guess that's my favorite. It is far from perfection of course but gives the best online experience to me. It also serves as a bookmark manager and a snippet library, though I use Breevy since a few months for this purpose.
The second place goes to Adobe
Fireworks. You may hear that Photoshop is the application for web design - no, Fireworks is.
I like
Notepad++ a lot but just a few days ago switched to
PSPad. So far so good.
PowerPro is also very powerful but I use only a fragment of it, some hotkey and window thingies. Sometimes I make scripts to spare time and then it is a real lifesaver.
Breevy is my new favorite. It's a text expander but a very well built. Unfortunately not free but worth the money. It completely changed my coding behaviour, speeding up the process significantly.
StrokeIt is also close to perfection in its field, I use it all the time.
I also have to mention
Dropbox, I use my usb stick only occassionally since I found it.
NexusFont is also a newcomer to me. Since I learned it enables to load fonts without instaling them, I use it whenever a new font is needed. Clean & simple.
I'm also a great
InDesign fan though nowadays I rarely use it.
And finally
Total Commander 
I like its simplicity and the internal file associations feature. It enables me to use my favorite apps by double-clicking on associated files, even without admin rights.