I must agree with Stefan. I too am fortunate to own an F430 and a GT. If push came to shove and I HAD to sell all my toys and keep just one it would be the GT. While I love the sound of the F-car, and I am one of those that really appreciates the technology of the F1 shifter option, I do get more pure driving enjoyment from the GT.
Reactions from other motorists toward the two cars are very different as well. Everyone LOVES the GT, but some are not so positively inclined toward the Ferrari. Driving at trans-legal speed is likely to get you a thumbs up from other drivers in the GT and a middle finger from the same people when you are in the Ferrari.
I cannot speak for Europe, but in The States, I would say there are a whole lot more "posers" that own Ferraris than GTs.
Don't get me wrong, the F430 is a great car, I recommend it highly, I just enjoy the GT more.