Sedan. Why? Well, when compared to sedan what does Coupe give you? Higher price (at least in Finland, dunno 'bout USA), more inconvenience and usually slightly less space in the back. Coupe might look slightly better than Sedan, but not good enough to justfiy the increased price anf inconvenience.
Honestly, besides the looks (which are debatable), Coupe gives you only negative things when compared to Sedan.
EDIT: Of course, I'm talking about REAL Coupes here, not hatcbacks (like VW Golf for example)