ha - yeah - I'd agree with you totally about the not having time to play a game like that exclusively, if I weren't married. But playing games by myself in what little time we have together (aka what little time I have off) just isn't good. I want to spend time with her, but I also want to play videogames. Up until we started playing WoW together I had been playing some Medieval II: Total War (amazing game) and some NFS: Carbon (not so amazing, but enjoyable). Both of these I could only really play much off and on... NFS wasn't so bad as its entertaining to watch for the most part. But Medieval II wasn't so good, long play periods that too an outside observer seem very boring.
I tried to get her to play CS:S. Medieval and NFS a few times, but all of them were too hard for her to get into (her parents never got their two daughters a console growing up so never had experience).
WoW was the perfect thing, she really got into it (more then me even for awhile), nice gentle learning curve and doesn't rely on having fast hand-eye coordination or particularly good sense of tactics off the bat. Having played WoW now we can probably start playing other games later as she's built up a lot more hand-eye coordination and has gotten used to games in general a lot more.
Its what we do with our weekday evenings now instead of watching a lot of random movies and other stuff we've downloaded, or having people over to visit all the time (not that I don't like my friends - but it got ridiculous entertaining 5 nights a week).