Post I made on another forum in response to the same question:
On my Macbook Pro I'm running:
Photoshop CS3 ($650-$1000) - I need it for my Uni classes. If you don't have the budget for CS3 I'd go with
Pixelmator ($60) You could use
The Gimp (free) but you have to use it through X11 which feels kind of messy.
Aperture ($200) - Love Aperture for organizing and doing basic edits of my photos. iPhoto is probably fine too though.
AppCleaner (Free) - some apps wont be completely removed just be deleting them, so I use AppCleaner.
Awaken ($13) - iTunes alarm clock.
iTunes Alarm (free) works too though.
Burn (free) - OS X does have disc burning capabilities, but Burn's a bit better.
CandyBar ($30) - Easiest way to customize icons and dock.
Cha-Ching ($40) - My favorite money management app. The other option is
Money ($40)
DEVONnote ($20) - I use it for note taking with automatic wiki links.
Final Cut Express ($200) - I do video editing for people as a side income, iMovie is probably fine for most people. iLife 08 is free with OS X, but I would probably download the, also free, downgrade to
iMovie 06. The interface seems more logical.
FotoMagico ($49-$129) - Great slideshow creating program. iMovie can produce ok looking slideshows as well though.
Google Earth (free) - it's just fun
HandBrake (free) - DVD ripper and encoder
iScrobbler (free) - iTunes Last.fm client
iWork 08 ($80) - iWork has a much better interface than Office. It's also just as good as Office for word processing, and hands down better that office for presentations, spreadsheets could use some work, but they're acceptable by my standards.
Missing Sync ($40) - iSync doesn't have great syncing capabilities for my Treo, Missing Sync fixes that
NewsFire (free) - My favorite RSS reader, people seem to like
NetNewsWire (free) as well though.
Quicksilver (free) - Amazing keyboard interface.
The Unarchiver (free) - Unarchiving program, if you need to unarchive .sitx files than the only option is
Stuffit Expander (free)
Transmission (free) - Favorite torrent program.
Transmit ($18) - Favorite FTP client.
Cyberduck (free) is good too.
Perian - Codecs for Quicktime.
Flip4Mac - WMV codecs for Quicktime.