I voted for Gran Turismo 1 simply because it was authentic, it was the original and it was simply the most mind-blowing intro I'd ever seen in the history of gaming (and I've been gaming for decades).
GT2 was awesome, the Cardigans brought that intro to life... BUT... without the soundtrack is the intro as good as GT1? And if I'm not mistaken wasn't the intro 'lifted' from the PS2? You can clearly see the intro isn't PSX-based and as far as I know, the intro was actually done on a PS2 dev-kit and the video plonked on the disc.
GT3... hmmmm it didn't really get me. Too clean, too crisp and too clinical. No emotions there at all.
GT Concept.. Now
that was a stunning piece of rendition. I'd never seen a Mercedes done in such detail before. It truly was a work of art, pity the rest of it was so plain (no pun intended).
GT4: Didn't like it. GT4P was a better intro in my opinion (loved the moving crowds).
GT5P... ohhh I was flabbergasted at GT5P. Unbelievable detail, stunning rendition, but the soundtrack was waaay too predictable and after years of having these soundtracks on intros, I think it's time PD moved onto something else. No more grunge please.
Apart from that though, GT5P comes a very close second to the original. The art and direction of Prologue is masterful, but I still watch the intro to GT1 on occaision and it still gets me, even to this very day.