The A5 is a great car. It comes with the 3.2 V6 with FSI direct fuel injection and 265hp. I would recommend the 6mt over the auto, but the new auto is worlds better than they were before. I also would recommend the S-line package because they look dead sexy and it adds the amazing 19" wheels which are my favorite Audi wheel ever made.
They are pricey though. A loaded A5 will be a few thousands MORE than an S5. I have driven both, and of course loved them both. The S5 has fantastic power, and the A5 has good power.
The new A4 can be had with the 3.2 and an auto, or even better, the new 2.0T with a mt. They are essentially the same car, and you can pick up an A4 for much cheaper, and with the new 2.0T with a chip, can get 330 crank tq.