Since my PC is on the blink, I've had to resort, of late, to using any damn system I can get my hands on. However, most of these don't have an IM or any music to listen to. For those of you who use MSN/ICQ/AIM/Yahoo! Messengers, there's hope yet: go to www.meebo.com and sign in on your service(s) of choice, and chat easily. I love how my contact list is intact, complete with user groups too!
As for music, last.fm offers the perfect solution. Just register (a very brief process), and download thier radio player. Then, you can search for music by tags or similar artists. The quality is pretty good, and works even on 64-kbps connections, skip-free. Give it a spin!