Linux is perfectly fine for GUI users. It's really great for most common use cases. You might have issues with games (or so do I've heard), but I'm not a gamer and don't know much about this... Steam has helped make games on Linux a lot better. I just play supertux or supertuxcart or mahjong once in a blue moon and am happy.

Most things work perfectly - stick to Ubuntu or Fedora or opensuse. Once you get the hang of things, things actually feel better on the Linux desktop:

• much faster than Windows
• no tracking
• highly customizable
• if you ever get into it, you can script your setup to be easily replicable across machines

Things that you'll have to fight

• fingerprint scanners - only a small subset work. My Dell latitude scanner works perfectly though.
• some printers might need manual driver download/install
• some software is only built for Windows (less and less of those these days, unless you're doing something specialized)