Weyerbacher Double Simcoe IPA is the standard as far as I'm concerned. It has incredible grapefruit and citrus flavors and is incredibly smooth for being around 9%.
I don't like a lot of Weyerbacher beers, most seem too hot to me, but this is amazing. Brewery is in Pennsylvania.
I am a huge fan of the citrus flavoring hops and this is one of my favorites, if you can get it on cask it's worth having someone carry you home.