Alternity is one that I have never tried, but I keep hearing about and seeing in the local second-hand store.

I will say that there's a definite sense of possibility to roleplaying that doesn't match other games. Whenever I see first time roleplayers, I recall fond memories of my own early groups (which, admittedly, were far too large, so we got up to far too many shenanigans).

I'm not much into the combat/strategy games and miniatures, but I've always wanted to try them more. I was into Battletech years ago, but I never played seriously.