I've all-of-a-sudden got an urge for a big magnesium-bodied semi-pro camera and have been handling the D300S, EOS 7D and looked very briefly at the D7000. These are all about twice as much as the D5100 and I am struggling to see any justification in spending on them given where I'm coming from, especially since dpreview.com rates the image quality of the d5100 above that of the older models. I can see where the money is going but as an upgrade, to significantly improve the clarity of my photographs, this seems at best a sideways step. The D7000 is annoying me as it is empirically better, but then did that make me stupid for buying the D5100?
So I looked at glass and there seems to be few options for the DX format as yet. I can't see a review of the AF-S 85mm f/1.8 DX G online- this is a lens I'm interested in. I want autofocus to work on my camera body. I'm not particularly interested in a zoom lens, I just want a really good prime. It looks like the AF-S DX 35mm f/1.8 G is a good buy, but apart from that, is there any justification in getting say a D300S or 7D other than my wanting something to play with that's more cool?
What do do about an upgrade when you've already got a really good enthusiast's DSLR?
[ please no-one say 'learn how to use it' :-) ]