Transmit
Billings
CSS Edit
TextMate
CocoaMySQL
KeePassX
Mail
Parallels
xSlimmer
I have mail set up for all the RSS, and email stuffs, which is nice with the Smart Box features.
Then the TextMate + Trasmit combo, I got CSS Edit, but I didn't need to, firebug works great.
KeePassX is great for keeping all the client data together and securely at that.
CocoaMySQL is more a more stable MySQL GUI
Parallels is nice to test for IE
Billings ROCKS for time tracking. It's a bit expensive, but it's seriously worth it.
xSlimmer is great for freeing up space.