My friends back in the day wouldn't shut up about KOTOR to the point where I never wanted to play it myself after I got a PC. I own it on Steam for some reason, but I've never played it (despite being a huge Star Wars fan). Maybe if the remake is good I'll pick it up in a few years and try it out. I always heard good things about KOTOR but the incessant gushing over the game turned me off.
-TBF, it was kinda a "you had to be there" kinda thing. Anyone going back and playing KOTOR now is gonna be severely disappointed.
I think it was the first, and remains one of the few, full fledged RPG Star Wars games (only other ones I can honestly think of are KOTOR 2 and TOR) made.
Combined with the fact that XBox was fighting an uphill battle with exclusives vs Sony, the game being developed by Bioware, and Bioware still being a relatively fresh company that hadn't ridden it's name and formula into the ground.
It was also the first "fully voiced" RPG where all lines aside from the players were voiced (major caveat being alien races of course spoke their native gibberish which was a lot of looped nonsense) as a more cinematic experience. Given it launched into Prequel Mania didn't hurt it either.
And lastly of course it was a legitimately good game with a great story and solid twist, knock off characters that gave people the warm and fuzzies and reminded them of the OT.