Tell me, is there any photos that a Nikon D90 can take, but entry level DSLRs like Pentax K-X, Sony A550, Canon 500D cannot take?
IMO, taking a photo is less of the camera, more of the photographer. In the hands of a good photographer, I dont think he/she will feel that he can take better pictures with a D90 than when using a k-x, A550, 500D/550D.
As for feeling inferior, then why buy D90? Its only an APS-C DSLR. Might as well buy a full frame, then she can pwn all her clubmates right? Her friends will be so impressed if she can bring a 1D Mk III to school