quite a big list of apps i would install on a new Mac but not necessary use all the time.
Chat
Adium - chat client for AOL, MSN, Google Talk etc clients.
Skype - video chat client
Media
CoverSutra - iTunes controller with desktop album art
Final Cut Express
Flip4Mac - QuickTime codec for Windows media
Handbrake - rip DVDs to mp4
MacTheRipper - rip DVDs
Perian - QuickTime codec for DivX, MKV, FLV etc
Shockwave (Intel)
VisualHub - encode video to other formats
VLC - universal video player
Web
Firefox
Coda - website developer
Suites
iLife '08
iWork '08
Office 2008
Professional
Photoshop CS3
MATLAB
Utilities
AppZapper
DiskWarrior - Disk recovery utility
Fan Control - MacBook fan controller
Google Earth
iStat Menus - RAM, CPU, network usage in menu bar
Little Snitch - deny internet access to apps
NTFS for Mac - allow write access to NTFS
Mac Pilot - enable hidden features in OS X
Onyx - maintenace utlilty.
Pacifist - custom install of install packages
QuickSilver
Senuti - iPod restore
Steermouse - third party mouse driver
SuperDuper! - bootable cloner
Transmission - BitTorrent client
Toast - Burning Utility
Unison - unenext newsgroup reader
Xsilmmer - removes space claimed by Universal Binary applications and languages
Virtual Machine
VMware Fusion
Widgets
BigPond Maxi Meter - Telstra BigPond internet usage
Countdown Calendar
iCal Events
iStat Pro - RAM, CPU, Battery etc info