My first impressions are that GT5 is going to last me a very long time. It's brilliant. There are many negatives but in the grand scheme of things the driving (with DFP) feels so right that one a race or time trial starts they all go to the back of my mind.
I'll start off with the negative, first off the graphics, they aren't as bad as some people are making out in this thread but they are not as good as I expected them to be. The shadows are jagged but it doesn't both me too much. The standard cars look bad when you stop and compare them to premiums, but during a race the only standout way to tell is that they have darker windows. you might notice the odd thing from time to time but it's generally not very noticable while your racing. The loading times can be quite long and it does freeze for a min or two on occasion but the freezing is a network issue and if your not playing online you can solve that by disconnecting your network connection. I imagine the freezing will be sorted out soon. They're the biggest negaatives I've noticed so far, but the positives far outweight these.
The first thing I noticed was a huge imrovment from GT5

was the sound, the cars sound so much better now than in GT5

. The engines hit deeper notes and there's a much better feeling of the engines power coming through the speakers. This is a huge improvment imo from past GT games. Body mods are improved, in GT4 we got a rear wing and an invisible front spoiler, this is still there for the standard cars but most of the premiium cars have more in depth body modifications from new front bumpers, splitters, cannards and rear wings. The choice per car is sometimes limited, but there are options to add body kits to most cars.
The second thing I noticed but of more importance to the sounds imo are the physics, I would say they are brilliant but I don't think that does them justice. I can imagine this game being hard with a pad but with a wheel it's absolutely glorious regardless of it your driving a standard or premum car, the cars drive just how you'd want them to and expect them to in real life. It's an improvment from GT5

, theres more feedback from the wheel too. PD have nailed the driving physics and it shows. If I was to compare it to a PS2 driving game Id' say it feels like a better, more advanced Enthusia to drive. There are notable differences between each car and different driving disciplines require very different approaches to how you drive the car. Driving the karts is vastly different to driving any of the cars, even the small Japense Kei cars, Karting is a blast as well. The Nascar racers sound thunderous and rattle and shake like you would expect, they feel powerful and heavy and you can feel them dancing over the surface of the track as though they're on the edge of loosing control, driving in a pack at 200mph can get pretty intense. I haven't tried any of the off road and rally races yet but if what I've experience so far is anything to go by they should be excelent affairs.
There's hundereds of songs to choose from on the game disk as well as the ability to import your own playlists into the game. The menu music is typical Gran Turismo which love it or hate it is a good thing imo. I haven't raced off road, in the rain yet or through a day/night cylce but everything I've seen and done so far is fantastic and there's no reason to doubt that those will be too. GT5 is not without it's flaws, most of them are graphically, but I can honestly say that during the heat of a race (short of over powering the opposition with a much better car and ending up driving miles ahead by yourself) that it's not that noticable.