I was expecting to buy an Audi A4 or A3 and I drove the GTI on a whim. It's a good thing that I did this because I bought the the 2011 model almost immediately.
This car is unbelievably fun to drive and it's economical, practical, reasonably priced (29k for the Autobahn package) and compares very favorably to every other car in it's class. The interior has an Audi build quality but costs a couple k less and the VW warranty is now better than Audi. The amenities included in many ways trump the Audis as well. For instance, the Bluetooth package on the GTI has the A2DP streaming protocol included as part of the base features. Not on the Audis, you'll pay extra & lose your iPod integration too.
Driving characteristics. The GTI hugs the road and immediately pops as soon as you ask for power. The stock Detroit 18" wheels are also a very nice touch and your need the wide tires to handle all the torque produced by the engine. Be aware that you'll probably need to buy Winter wheels if you live in northern latitudes. The GTI's stock setup is not going to get you through heavy snow very effectively. I purchased a nice set of snow tires & rims for $750 and put them on myself. A small price to pay for this much fun.
It would be nice if the phone interface would be able to transfer my contact addresses to the satellite navigation system. It seems odd to me that this level of integration was overlooked by the designers.