GTI MK6 - Looks great but I dont like the way it drives as much as the MK5. Doesnt sound as nice either imo.
S3 - Absolutely love driving S3's. Suppose it depends what you like from a car but for me just the way you can set off in it is a winner.
Focus RS - Not driven the RS but the ST did make a nice noise but the cabin isnt anything to scream about. Not a fan of the styling tbh.
BMW 1 Series Coupe - Great looking but for me they just seem to be a little boring inside.
A3 170TDI - Im still a fan off the 170 engine as long as its not the new common rail engine, it just didnt seem to drive like a 170hp car
So if fuel is an issue then I would say the A3, if not then the S3. Just go test drive and im sure you will make your own mind up.