Jowel, I can't remember but I don't think Focal length and Field of View have come up in your astrophotographical musings so far. Apart from the weight/balance difficulties of a 10" dob on an EQ mount which will make your learning curve that much more tricky and frustrating, the longish focal length (usually 1.2 metres) and tight FOV (about 45x30 arc mins?) means your tracking has to be spot on (one of the hardest things to get right when you're learning) and your view is quite tight and "zoomed in".
This is the other reason people like high quality refractors like Tak's - wide FOV, shorter FL (around 700mm) to get in more sky, wide imaging circle with very flat FOV. There's an excellent freeware application called CCDCalc that let's you gauge the effect of these variables on commonly imaged objects that might be worth a play if you end up seriously planning things for imaging:
http://www.newastro.com/book_new/camera_app.php
These are also reasons why I like my 8" Newt (with an MPCC for handling coma) - vignetting not too much of a chore, flat field, FOV about 1 degree, focal length long enough to zoom in a bit but still not too long to make tracking a PITA. This is a very personal choice - you'll hear people haggling about wide field versus focal length. You can't have a beautiful widefield milky way or andromeda shot with doing lots of mosaic work with a long FL, but then neither can you see detail in galaxies or the horsehead with a widefield refractor (without barlows, Powermates etc....). Hopefully this will help you see there is no "ideal" astrophotography rig - its all about choosing the right tool for the flavour of AP you end up preferring (which you don't know till you have a go anyway).
Going 12" and these things all get harder (balance, FL & tracking, OTA/focuser sag, mirror mounting, tighter FOV).
As others have said, you may well be much better off getting started on visual though, and the added aperture benefit of a 10", 12" etc is very significant - something worth checking out by looking through different scopes if you can at all manage it.