The audi is a nice nice niiiiiiiiiiiiiiiice car. The attention to detail is amazing. BUT, if your getting a 2.0L A4, that car will be Boring with a capital B. If you are in love with the styling or cant get over the Audi interior, get the A4.
The camaro is a cooler car. Better styling. Interior isn't nearly up to par, but its got a better engine as which will make it a more enjoyable ride. Id get the Camaro, its the hot car, and its the one you will look back on as being a good buy... rather than the nice but generic audi which will be duplicated a million times over.