Hi, hope you don't get flamed too hard for the question as it's asked a little more often than others...
Obviously you are going to get VERY biased answers since you looking for personal bests, but I will do my best to keep towards answering your question. Although, you really should try this:
Go over to www.freshmeat.net
and type in each program you want. Say you want an mp3 ripper, type in "mp3 ripper" and search. Try out some of the options there, and find your personal best. But to get you started:
Best Mp3 player in X: xmms
In console: mp3blaster
Best Video Player: By far, mplayer www.mplayerhq.hu
Best chat program: Gaim
Must haves: Depends on what you wanna do with your PC.
Graphics, always go to Gimp.
Word processing, I have lately preferred Abiword.
Boot Manager: Lilo
System information: Gkrellm
Windows Manager: Flux
Mail client: Good ol Kmail from KDE (although I have been wanting to give sylpheed a try)
Useless CPU clock cycle dedication: Seti
Memory Recovery agent, not really necessary, but you could see if you have mem problems with memtest86 (I believe is the name).
FTP server: Proftp
FTP Client : gftp or simply pure CLI ftp
Sounds about good for now