"Weighing up":
Linux can do everything Windows can do, do it faster, and do it for free. Period.
You'll need a really small distro if you want to fit it into a small drive and still leave windows alone. If you can dedicate a drive to Linux, then it would be great.
Pick up a second HD, even a 1 gig is lots for Linux, and then download and install any distro you like.
Mandrake 8 is probably the easiest to start with, but it's also really big.
Take a look at Linux4win,
http://www.linuxmandrake.com/en/lnx4win.php3 if you just want to get your feet wet.
Check some PC magazines, specifically "Maximum Linux", which includes a CD, usually with a couple of smaller distros on it, for you to install.