Speaking only in terms of GTI vs TDI, I chose the TDI simply based on the mileage. Having owned a 2003 GTI VR6, and then a 2006 GTI MKV 2.0T, I can point out a few things. My commute had been 6 miles or less of purely city driving with 11 stop lights for both of the GTI's, so mileage wasn't that important to me. I think I averaged around 21 mpg in the VR6, but MAN i loved that 6 cylinder pull in that little but heavy car. When I stepped up to the 2.0T, I couldn't beleive how similar the power was to the VR6, and how much better the mileage was. I probably averaged around 26 mpg for that short city commute. That doesn't sound like a whole lot, but when you get that thing on the freeway, you can really milk some good mileage out of it. That was the beauty of that motor to me. I could really rip it up when I wanted to, but at the same time get great mileage if I babied it on the freeway. I remember one trip where I absolutely ripped up some twisties in the country roads all weekend and found the true intentions of the car's performance. When it was time to head back home, I used Cruise Control, with the Air Conditioning on, but went the exact speed limit for about a 3.5 hour trip. Door to door I got 38.3 mpg, which is obscene when you consider what it was able to do in the twisty roads. I don't think there is any other motor like the 2.0T on the planet that I know of. Well anyway we moved to the country and I now have a 21 mile commute with very few stops. I went with the TDI and so far have been averaging between 46-50 mpg per tank. That being said, it is still really snappy when you want it to be. The corners are a little mushy, but for everday driving it is a much smoother ride. A decent compromise in my opinion. I love the car, and didn't see anything in the other cars that would make me considering one at all. Yes the VW's are quirky at times and entertain electrical gremlins on a regular basis, but the fit and finish is spectacular and the overall product is like nothing else out there. Had I not moved to having a longer commute, you best beleive I would be driving a new GTI or waiting for that Golf R, but for now the TDI gets me there currently at 49.1 mpg on this tank, and allows me to have some serious fun at the same time. The power and fuel efficiency of both the GTI and the TDI will surprise most anybody. Do your research, drive them both, make your decision. I miss my GTI's so much, but I do not have an ounce of regret for getting the TDI. I love it equally!