I'm about to embark on a heck of an upgrade: D40 to D700. I plan to hang on to the following lenses: 50mm 1.8, Sigma 50mm 1.4, and 35mm 1.8 (by all accounts, it's fine on FX, albeit with some vignetting). What should my next prime be? I don't do a lot of landscape photography, so wide angle isn't a huge priority. I'm thinking 28 2.8 and 85 1.8. Any other thoughts/recommendations?