Hmm, well I love NWN and I personally think the story is pretty good. Its not amazing but it is good. With all the mods NWN could keep you busy for years... I've heard NWN2 is rather nice too.. I personally like The Witcher, and I just finished Mass Effect which I liked...
I've never been able to understand why/how people recommend Baldurs Gate and Diablo so much. I just don't like them. I don't like the interface, I don't like the combat and altough the story may be good I could never get into it... But who know maybe you'll like it... Fallout is pretty good too and both of the Knights of the Old Republic games are a must, especially if you liked Mass Effect because you will notice quite a few similarities... Dang, now i want to break out KOTOR and play it... I just can't seem to find it though, maybe I'll have to buy another copy...
Hmm, lets see, Oblivion was pretty good, lots of mods for it and the storyline is decent... Fable is good, I thought Freedom Force was, quaint... If you like GTA Vice City, you need to try GTA San Andreas as I personally think it is a better game... Have you tried Warcraft 3? Some of the strategy RPGs are fun...