Having driven the 2010 GT, I can definitely say that it is both a fun car and a more refined car, but it is certainly not a cheap car. The one I drove was optioned out to around $33k, with the premium interior and driver information center. In a Camaro, that's 2LT trim, equipment and power levels for several thousand more. However, you wife does not want a Camaro.
A 2008 or 2009 left on the lots at this point will be a much cheaper proposition, and despite the improvements and refinements, it is hard to justify the price difference.
Have her drive one anyway and see what she thinks.