Just a note: Hotmail and email are the same thing, just one is throughly spammed with junk mail even if you don't use it.
ICQ.. well, I forgot my #.
AIM (you missed): Decent, but no custom names. Good Away Message system though.
MSN: Custom names, no ability to set custom away messages without external program.
IRC: Custom names (sorta: nicks). Away Messages. Chat, PMs.. all good.
Xfire (you missed): Strictly for gamers. Its okay.. no away nor custom names.
Integrity (you missed): Not sure, don't use it much.