Here is my small list again. :-)

I recommend & love the following applications:

Adobe Photoshop
BetterZip (great unpacking application)
CandyBar (skin your Mac, use MacThemes as a great resource)
Colloquy (best IRC client)
iLife & iWork
Little Snitch (must need)
OmniWeb (perfect Browser, I love it even more than Safari now!)
TextMate essential editor!
Transmit / Flow (as SCP/FTP Client, I prefer Transmit)

Have fun.