Yup. The new A3 is out. The new sportback A3 was released for order at the very end of the year and the first ones are yet to hit the streets due to the ridiculous lead time for a VAG car (4 months when i enquired about the new sportback). The new S3 will be out very soon, it's already been reviewed by a few magazines/sites.
I had an A3 sportback, although it was a diesel the car is generally the same. Surprisingly spacious and very practical. The biggest weak point of the car for me was the interior, an area that usually gets praised on Audis. The seats were absolutely rubbish compared to BMW sports seats so you would need one with the bucket seats. The centre console in particular is very dated and the RNSE system (satnav unit) is so dated it's like using an abacus. It was very solid, well built and didn't squeak though.
If you are serious it might be worth doing some digging over at Audisport.net. Not as good as here obviously, but I remember a few owners giving an honest opinion of their S3s and that was generally that they are a bit uninvolving even when tuned to the hilt. I personally think that a Golf is a better option, Mk6 GTi with a remap and some other bits. I actually think the 1 series is better than both but then I would say that