After reading @SadPSPAddict 's review of GT on the PSP I have been convinced to put the game at the top of the list. Rather than concentrating on the lack of structured career mode, he went into detail about how that makes the game, in a way, better. I now realise that I can customise the entire game to my needs, my favourite tracks, cars, and my playing style in the best racer on PSP.
Having said that, I won't be getting it for a while. I still have too many games to play + complete and I will get that game in February instead of Halo 3: ODST!
Thanks SPA!