I third Arx Fatalis, it basically
is UW3.
Blood-Pigggy is correct in that Elder Scrolls 1 + 2 are heavy RPG games (and are huge games), but can get very repetitive. However, the best game in that series,
Elder Scrolls III: Morrowind, is a masterpiece. If you can get your hands on it, I highly recommend it.
System Shock 1 + 2 are more FPSs with an RPG element in them. System Shock 2 is a good one to try though.
In my opinion, having played all the aforementioned games, Morrowind is likely the closest modern equivalent of the UW experience that you're likely to find. Barring that, Arx Fatalis is your game.