I also recommend downloading a linux image file, putting it on a USB stick and booting your computer from it. This lets you try out linux without making any changes to your computer. The other nice thing about a live USB stick is that it lets you make sure that linux detects all your computer's hardware. If you don't have any problems during the live session, you won't have any problems when you install it for real.
Another vote for Linux Mint. You can always try different linux distros later on.