must have softwares (for me), plz use google search for locations or just goto macupdate.com , ps, all of below softwares are free, or shareware without function or time limitations.
1. adium, messenger, support AIM/Yahoo/MSN
2. Azureus or Transmission or bit rocket, p2p bittorrent software
3. firefox/thunderbird, browser/email
4. comicbooklover(share) and ffview, read comic books
5. coreduo temp/smcfancontrol, check your CPU temperature/control your fan speed
6. cyberduck, ftp client
7. mac the ripper/DVD imager/DVD remaster/ ffmpegx/iSquint/ Handbrake, DVD ripping
8. flip4mac, play wmv file in quicktime
9. frostwire/aMule, p2p
10. Gimp/Seashore photo editing
11. google earth
12. VLC/mplayer OSX universal media player, play anything, divx, xvid, h.264 etc, etc
13, neooffice, openoffice, free office suite
14. OnyX, really good stuff to maintain your system, it recovered 6G space for me once.
15. plot, mathematical plotting
16. quicksilver, application launcher, better than spotlight
17. Realplayer, only once can pley real video file on osx
18. skype/sightspeed, messenger, allow video conference with your buddies on windows.
19. stuffix, expand any compressed file
20. virtual desktops, fabulous animated switch desktops, much like OSX 10.5's "space"