I'm going to have to second Arcanum. That was one of the best RPGs I've ever played. (I've played baldur's gate series, icewind dale, nwn, dragon age...)
Arcanum:
I will "third" it. Good story. Mix (?trade-off) of magic & technology. Party based (but can solo most of it, if you really want, on a replay). Lots of MODs. A true RPG since you can develop your main character any way you want (and develop your NPC companions any way you want with MODs) and can solve most quests several ways (good, evil, with violence, without violence - cunning or persuasion, etc). Worth a replay immediately just to try out different things. And worth a replay every few years.
But if you go the tech guns route, be sure to get the MODs. The guns were underpowered. My main went the tech backstab thief route, but that is just me
KOTOR:
Too bad that you did not like KOTOR. I bought it clearance-bin priced, did not expect much, but thoroughly like it. It is also worth a replay every few years.