This. The only game that got me deeply addicted. First xbox, first LIVE membership, I felt like I discovered a whole new gaming culture. Countless nights spent waking everyone up from uncontrolled screaming..
Age of Mythology, Fallout 3, Skyrim, Sim City 2000 (I think?), Roller Coaster Tycoon 2 (best one imo). All super fun and addicting. Oh and WoW, but you already covered your situation.
dont downlaod mods until 1 playthrough, i got to vegas and downloaded a shitton of mods like zombies everywhere and bullettime and it ruined the game, well, not really, but yeah