This winter I played Skyrim for 100 hrs, and then ran out of content.
I booted up ET and happily began.
Played about 60 into Dragon Warriors VII, and then ran out of content.
Back to ET.
100 hours into Diablo 3, and then came back again.
I have a friend who does the same thing with Super Smash Brothers: Brawl. The thing is that both games take a high degree of skill, are generally short, and have a learning curve that goes on forever. Other games depend on content, whereas ET (and super smash) depends on skill.
I enjoyed certain moments in Diablo 3, Dragon Warriors VII, and Skyrim WAY more than ET, but they fade...