Now I generally like the original Xbox, though not always for the same reasons as everyone else, but there are certainly some good games on it. Most people saw it as an FPS/dudebro console, but in terms of RPGs, which rank as the best? The most frequently touted are:
-Arx Fatalis
-Beyond Good and Evil
-The Elder Scrolls: Morrowind
-Fable
-Jade Empire
-Star Wars: Knights of the Old Republic 1 & 2
-Sudeki
From what I've played, Sudeki is the worst of the bunch. Fable is decent if taken as just a fairly linear, western action-RPG take on Zelda rather than the massively 'free, open-ended' quest it was falsely advertised as. Beyond Good and Evil certainly beats it in every regard, though. It has the same length and action-RPG feel but is infinitely better in every aspect. Morrowind didn't look like my cup of tea but people were generally very fond of it. I only played a little of SW:KotOR but it had promise and I'm looking to get a copy in hopes that it will fill the void for a solid WRPG on the system that actually lives up to the praise. Never played JE. Can't say anything about Arx Fatalis either but it also cited as an underdog. I won't even mention X-Men Legends. That thing was totally a product of its time, a revamped Baldr's Gate: Dark Alliance and sold because of the hype and license backing it. There are probably others that I haven't mentioned, so let me know what I'm forgotting.