Okay, I cancelled the WoW account. Too much travel time, not enough actual game-playing. It was fun, but not fun enough to keep paying for, and I just didn't feel emotionally invested in any of the characters I was playing.
I think part of the problem is that it's a stuff-based game. The rewards are in new and better stuff for your character, delivered on a relatively regular basis as you level up. The problem I have with that is that getting stuff for the most part doesn't give me new things to do. City of Heroes, in contrast, delivers a lot of character improvement early on, with the rate of improvement slowing over time as leveling gets slower. This means it's easier and more fun to create alts and have meaningful differences between them, as the various power sets play differently. Also, you get to choose a custom look right away, as opposed to the WoW problem of every Night Elf going through the "green bike shorts, leather vest and Boy Scout neckerchief" look at level 6. Seriously, ever single one of them looks identical except for the hairstyle and hair color. That's not enough variation for me, I'm afraid.
So it's back to City of Heroes, where the Invention System delivers new ways to customize characters.