I just bought my first NSX a few weeks ago, a 2000 Red/Tan NSX. While searching for an NSX, I was set on the 91-01 versions. However, when I first went to look at my car at the dealer, they also had a 2003 Red/Tan NSX on the lot. After agreeing to buy the 2000, I had to wait a few weeks to buy in order to avoid property taxes for a year. The whole time I had this sickening feeling that I was making a mistake and that maybe I should go with the 2003. I stuck to my guns, though, and now I'm loving the 2000. I've been forced to drive it to work every day this week and I just love walking up to it in the parking lot on my way to go home.
I will admit that the 2002+ version is growing on me. I'm still not crazy about the headlights (they look like some sort of weird eyes or something), but they're growing on me and I'll admit they do look more modern.
So, for now my vote is with the 91-01, but I don't think you can go wrong with the 2002+. I really think the new lights are just like a good adult beverage - they're an acquired taste. At first, they don't taste great, maybe even kind of gross, but then they start to grow on you to the point that you love 'em. This poll just proves that point, as it is a lot closer than the poll that was done just after the newer model was released.