Or whichever one you want to make your poorer, faster.
The PS3 has it's pluspoints like BluRay, but it soon gets boring. The lack of Anti-Aliasing in almost all its game frustrates me, as does the lack of any proper car games. The 360 has a much better online system, and the way it invites your freinds to games and private chat's is very clever and works incredibly well.
The only reason 360's get such a hard press, is that Microsoft rushed realeasing it, so that they were the first "next gen" console on the market. Therefore, the software and hardware was unrefined and failed alot. Now though, its all sorted and alot less people are getting the RROD, and if you do, its easy to get it sent back and does not take long.
As for the way the consoles look, does not bother me in the slightest. I wouldn't give a crap whether my 360 was just a boring triangle shape. Aslong as it plays game, thats all that matters to me. I also find the controllers alot better on the 360. This can be proved as microsoft have won multiple awards over the years for there controllers comfort, and they have spent alot of time making the controller. I find the PS3's controller too small, light and the triggers are way to sensitive, often resulting in accidental button pressing.
As for gameplay, both consoles are around the same. The processors are different (PS3 has nine cores opposed to the 360's 3), but both put out the same power and performance and the graphics cards are similiar specced. The only difference in graphics would be that the PS3 does not use Anti-Aliasing in alot of there games. Alot of people say thats not true, or that they dont mind it, but it is true, and i personally find it very annoying and distracting.
Also, if your looking for more racing games, then a 360 would be better. The 360 has forza, with forza 3 coming in october. Sure, GT5 may end up with more content, but the physics are most likely going to be superior, atleast judging from GT5:P's physics, as they are terrible.
If your worried about a G25 not working on your 360, then you could always save up your pennys and buy a fanatec wheel. The fanatec wheel's are far superior to the G25's, but the price reflects this.