I've used Ubuntu a few times, but Linux just isn't for me. I like to play games, and games aren't really Linux compatible. Yes, I could use a Virtual Machine but not all (i.e resource intensive) games work nor do you get "full" hardware support and considering I've spent over £300 on a graphics card, that's a massive no-no.
Dual Booting isn't worth it either. I don't want to reboot to do my daily tasks and reboot once more to play a game.
I have a Ubuntu LiveCD, which I use whenever I need to modify my Partition Table (while using the machine) if i'm working on a friend's system that's infected with viruses (to copy over personal files to a Flash Drive).
Although I don't use Ubuntu much, I can say that it's the best Linux Distribution I've ever used (this is coming from someone who as used at least 5 distributions).