Second Life.
I was really irritated at first. I was totally overwhelmed, the controls were shitty, and I couldn't figure out how to make my guy NOT be a fugly elf anymore.
Now, though...
I've gotten the character builder down. Solid. I know what I'm doing with it, it has a LOT of options. AND, if, say, you want to wear something weird, like, say, Tidus' pant-things from FFX, YOU CAN MAKE IT.
So far, I've made two characters, a guy and a girl, and I've made the Buster Sword to accessorize with. It even has the little holes in it!
...The controls are still shitty, though. I'll get over it though.