Good suggestions.
VLC must have.
I use Cyberduck for FTP.
Firefox for browsing.
Skype for videochat.
Azureus for torrents until native utorrent comes out (Azureus is CPU heavy).
CS3.
Cabos (like limewire but simpler) for Japanese DL's.
Some handy dashboard apps, get what you think you'll use.
I had Flip4Mac but after having some trouble with iWeb I checked the Apple forums and discovered there was an issue with it, so I deleted it.
Oh, and while VLC plays pretty much everything hassle free, the scan/fast forward doesn't really work smoothly and WMV files break-up when skipped forward back.
One last one I forgot, when I only had a CD burner back in the day, I was unimpressed by how the OSX burning software seemed to take up so much of the disc so I would say a decent burning app is also a must have, I use Roxio. I cant say for certain if Roxio uses less space on DVDs though cos I havent checked.