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