With the Ubuntu Live CD, you can do an “install inside of Windows” that’s pretty neat so you can try it out and try it on and see if it’s the distro for you. If you do decide it is though I recommend doing the actual dirty work and partitioning and installing it and all that–when you do the “install inside of Windows” option you’re limited to (I think) 30GB and you run outta room on that pretty fast these days.
I’ll unabashedly say that I originally chose Ubuntu because I liked the orange and brown color scheme, it was “warmer” than all the other cold, blue distros. (Most other people hate it and think it’s ugly, but the 8.04 Ibex desktop is my favorite!) It was that or straight up Debian, and I just liked the look and feel of Ubuntu (which is Debian based) best. It’s definitely the most user friendly, and I’ve installed and am using it on 4 different machines. Everything was plug and play, right down to the wireless, I just partitioned, installed, and magically everything worked. Actually, I think I had to remember to do apt-get update to get mp3’s to play but that’s painless.
I’ve seen a lot of people recommend Mint too, for pure plug n’ play ease of install and use. If Im’ not mistaken, it’s a Ubuntu variant.
I use it at work too, though I also maintain an XP boot because we have some Windows only software. I was able to get Rhythmbox set up and I can share music (via DAAP) and others using iTunes on our network can see and share with me too.
Give the Live CD “install in Windows” a try–you can always just uninstall it. Good luck and have fun!