There are just so many possibilities that a certain 3 can't be names, although the F-14 and F-22 would be up there.
Gorund attack, I'm sure the A-10 would be near the top.
Bomber, B-2 for sure, B-52 and B-1 aren't bad.
Helo Gunship: AH-64D would prbably be first or second.
I know that all of mine are American, but that's because I see them so often. I've never seen a modern MIG or Sukhoi or anything to compare them too.