Another thumbs up for the A3 – I bought a 2.0 diesel sport at 18 months old and still have it (- it's 5 years old now). I intend to keep it for another 2 or 3 years, as it's the best car I've had, goes like a little rocket, and is reliable. Took it to Chamonix last year and off to northern Italy in it shortly.
Only gripes: watch stone chips on the side of the car – they WILL corrode if you don't treat them. Black paint on one of the pillars went … Audi not interested, as "trim", so not covered by the bodywork warranty. The local dealership were very sympathetic and did it at cost for me.
Apart from that it's great! (Audi TT would be car of choice though, if I could justify having one).