Mac Apps I Recommend:

Adium (Chat)
Cyberduck (FTP Client)
Disk Inventory X
Dropbox
Fluid (Any Webpage becomes an app)
Google Chrome
Growl (Event notifer, works with a LOT of apps)
Quickboot (Menu switch between mac/windows if you're using bootcamp)
Skype
Spotify
Steam
TextWrangler
TinyGrab
Tweetie/Twitter for Mac
VLC
World of Warcraft [ ;) ]
WriteRoom