You know I played NWN2 heavily pre- WoW and loved it. Strangely I've never been a fan of the Diablo series, because I see it as just hack and slash. I love party-based games because they require more thought in my opinion, But I know I'm in the minority there.
it depends on taste of course but if u liked rp type games then i would try mass effect..... its not reaaaally rpg pure but i liked the rp parts of it a lot with a great story..... if you like scifi as well as fantasy anyway
oh of course you have to play it bootcamp
also the witcher is interesting but lots of running around again its bootcamp tho
i should play bg2 again...
oh yes and the knights of old republic games are greeeeeeeeeat or well the first one is if you like scifi and starwars.....the second one is not finished and so the ending is very very very very very dumb but you can play kotor1 in osx so try that