Romulans! Rihannsu ones especially, not the TNG garbage.
But what about those Vulcans?
Romulans, I say!
Vulcans. The TOS variety (amazing how TNG and beyond did such a $*#@ job with both Vulcans and Romulans.)
Oh, what can I say. The pointy-ears, smarts and passion of both races get me every time.
(But definitely not those bikers of the galaxy, the over-used and overrated Klingons.)