Forgive the abrupt reply, but you generalised and didn't specify TES vampires, in which case I would've agreed seeing as the only example of a vampire within TES that I can't say was evil was Lucien Lachance. If he was evil because of anything, it was his involvment with the DB, but even they cannot be said to be evil.
The Brotherhood are a cult of murderous assassins. They get paid to kill and enjoy it. Vincente Valitierre (sp?) leads a cell of the DB and is a vampire. The only genuinely sympathetic vampire of the whole lot is Janus Hassildor. He's the exception, not the rule.
Why do people love to romanticize bloodsvcking parasites that were created by the King of [censored] for the explicit reason of flipping the bird at Arkay? The very first vampire in TES was created by Molag Bal via [censored], the Cyrodiil clan made a pact with Clavicus Vile so that they would be able to troll their prey more successfully, there's a vampire who went and helped a vampire hunter just to screw him over for kicks...
Evil is evil, people. Vampires and werewolves in TES don't adhere to Underworld's mythology; they're far closer to their real-life mythological counterparts. There's no hint of any sort of factional dispute between vampires and werewolves in TES. Just because Underworld loves the concept doesn't mean a thing, when the lore creators of vampirism and therianthropy (Molag Bal and Hircine) have nothing to do with the other, nor have the races interacted in any meaningful manner.