Well Oblivion was awesome, And Morrowind is apparently good.

Personally however there are two text based games I'm really into, One is Torn, and the other is NationStates.

I tend to run both in the background constantly. Plus with Torn there's a hugely active forum which I quite enjoy xD
Nationstates basically puts you in the role of a leader of a country, I somehow made Organ donation mandatory, Needless to say I enjoy them both!

If you've got some time to kill I'd advise checking them out, Or not, Up to you guys :P

mount and blade warband

I LOVE this game, its easy to pick up and easy to run. Also offers lots of replayability and mods. Totally worth the money imo

World of Tanks

A free to play pvp based game involving historical tanks. Lots of mods, easy to pick up, free, fun. Can also run on pretty much any computer. Just make sure you have a few hours to install