Haven't played IX, but I don't know too many games like Ultima...there's a few games that have the same (or at least similar) degree of freedom and consequence, like Fallout, STALKER, etc...Planescape is supposed to be really good, but I haven't gotten to play it yet.
Don't play too many MMOs, but there's a fan-made game using the 256 color Ultima IV graphics called EUO (Egg's Ultima Online), it's got a lot of that oldschool Ultima flavor. But if you think UO's graphics are outdated, you definitely wouldn't like EUO.
The Underworld games are a pleasant diversion, though not quite the same as the main series...much more like a dungeon hack version of Rogue, without the randomness.
_________________
I'll brave the storm to come, for it surely looks like rain...