Well about 2 weeks ago, I switched to Ubuntu Linux and have been happy with it. It's very nice, came with a few things that so that I didn't have to download them(GIMP: Equivlent to Photoshop, Mozilla FireFox, GAIM, Open Office Suite, XMMS, and so many more things). I downloaded the flash, java, and many other plugins I needed with ease. You don't need alot of Linux knowledge to use Ubuntu. So Windows users you should all scurry over to ubuntulinux.org and order your 100% free cds, or download it yourself. 64-bit processors are supported, as are apple computers.
feh, I feel like a salesperson.
Ubuntu, as well as Yopper are based on Debian. The advantage of using debian is the apt-get prepositories where you can easily install new softwares and update current ones, it is very easy and so painless...
I used various flavours of linux for 3 years now and I completely dumped windows 3 monts ago.