I find that a combination of Simcoe (during boil) and Nelson (flavor & aroma) makes a very nice combination for hoppy brews. I usually start with these for my hop-rich AIPA's, and fill in with other hops at FO and dry hopping.
Amarillo, CTZ, and Warrior are also great high-alpha acid hops for bittering of IPA's. For flavor and dry hopping, besides Nelson, I like to add Northern Brewer or HBC-438 (an experimental hop designed just for home brewers).