Most are already mentioned, but i'll throw in my two cents anyway:
Lanun: best economy out of the gate, expecially under hanna.
Svalts: forest economy + Azalkan's mirror.
Calabim: why stick with 1 unbeatable hero, when you can pump out an army of 'em? In my recent calabim game, i won a conquest victory on a large map with 4 vampire lords, over 1k exp each, as well as 4 brujah's and about a dozen normal vampires of 200 exp+. Raze these guys early or be steamrolled.
Kurio->infernals. Do it right, and you can get hybbie out when most AI's have only just reached axemen. Annex an AI empire and you've got an economy.