It depends a lot on what the dragon's "for" to me.
In general, I prefer slender dragons with narrow heads and large wings (probably not realistic-scale, but pretty big compared to their bulk). Four legs, but they're never the focus unless they're on the ground. Sort of the Leer Jet of dragons.
The line for me blurs with eastern dragons. I prefer my dragons to have wings, but legs are actually pretty optional.
But, if the dragon's supposed to be a cavedwelling terror in melee, I'd lean towards a bulkier build. Smaller, but intact, wings and everything else being shorter and thicker.
Cheers!
Kinak