Nikon D5000 vs Nikon D60 vs Nikon D90: Paul Christensen’s Opinion – Quite a lengthy write-up there.
Having shot extensively with the D60 myself, owned and sold the D90, and now proud owner of the D5000, I can confirm that the image quality on the D5000 is at the same level with the D90, and both cameras have better image quality in terms of dynamic range, tonality and low high-ISO image noise than the D60.