Linux is no problem as long as you aren't playing games on your computer. That is, proper games, not just web based flash games or solitaire.
On Linux you've got enough programs to do common stuff. You've got OpenOffice for all your office-suite needs, Gaim for MSN, AIM and other instant messengers, XMMS for audio playback (looks surprisingly similiar to Winamp), and 99% of all viruses will not be affect you, because they are written for windows. You've also got a built in firewall.
This stuff is included in most new distributions, along with tons of other software. Note that you can not use windows programs on Linux without using an emulator, but you can'r really expect that anyway. Afterall, it is not windows :p.