As title says.. I've downed at least 30 of the scaly guys and it never gets old for me.

Personal favorite are the word-wall dragons.. They seem to be a bit stronger in both health and damage than other dragons of the same variety. I find that dragons are MUCH MUCH more satisfying to play against on the higher difficulties, specifically Master, if you can stack enough elemental resistances to not get charred/frozen instantly.

Anchient & Elder dragons look amazing.. Though Alduin (who I still haven't fought even once) looks absolutely beastly.