I like Sinnoh, Unova and Johto the most. Johto has a special place in my heart, but Sinnoh's myths and geography was something I really enjoyed. Unova of course is now the most interesting region, since it's so new. But I might go with Sinnoh, really loved that region.
Never liked Hoenn much, unlike the most of you. Kanto is just so boring and already seen region.