"Non-linearity" is bloody overrated. As DATD said, sure, Morrowind is non-linear, but it doesn't have much of a story, either. If I must trade a focal story for non-linearity, then give me a relatively linear game any time.
And now, gushing about KotOR...
I loathed the NWN OC with an unholy passion. I love, love, love KotOR. It redeemed Bioware in my eyes and made me pick up HotU (which, while no match for KotOR, is a quantum leap from the NWN OC and SoU). The graphics are not state of the art, but they are good enough to be immersive, and the melee combat animations are the height of cool. (Repetitive after a while, but still pretty damn cinematic.) The voiceacting is top-notch, and so is the writing. However, yes, it's linear -- but that, for me, is a plus. It is something of an interactive movie, and that's perfectly fine. The characters and story absolutely grabbed me, and I actually grew to care about them. Which is saying something, since I'm generally stone-hearted enough that I look at most fictional characters with analytical detachment rather than emotional attachment.
Now, it's got flaws. The AI is less then stellar; movements can sometimes be jerky; inventory management is a pain. But even so, the fun factor was large enough for me to keep me playing, which is saying something. I have never been particularly interested about Star Wars, and still am not (well, I have to do some research, but...), but that doesn't detract me from enjoying KotOR.
