I used to play a lot of Age of Empires - I love war strategy games - although my favorite was Dark Reign.
The killer though was Diablo II LOD. That was soooo addictive - nearly got divorced over that one. Even got to the point of going home for lunch just to sneak in a few magic find runs. The makers of Diablo have recently released Hellgate London which used a lot of the same principles. Apparently very good, but with young kids and my kiting addiction I haven't got a hope.
COD, Unreal Tournament and the shooters are great for gaming nights with everyone in the same room. Have done a few where we start at midday and go through until 3am. You try to go to sleep but can't your head is just spinning, eyes flashing, pulse racing - its nuts. I can see why there are issues with epilepsy.
[Edit] Also - My 18 month old has a serious neuromuscular condition that will effect his mobility and confine him to a wheelchair for what will probably be a pretty short life.

I am hoping that pretty soon I can get him on the computer/playstation and teach him to whip my butt

- at least it will by my excuse to be able to play computer games again! His older brother can go and kick a ball with mum