dragn priest = lich with dragon friends. so lich would win no matter what (liches always have at least a small army of undead and great power, manimarco was a lich, ya know, he could kill anything*)

*please ignroe that fight in oblivion, lets just say traven gave you skooma and you imganied the entire thing (then he OD'd and left the guild in your charge), makes more sense than killing the king of worms

No matter how much I love Vampire Lord, I cannot ignore the Dragon Priest's high damage fire attacks...so Dragon Priest

All of that was made up. A lich is just a dead body, whose retained their soul. Most spellcasters (not exclusive to necromancers, if you had paid attention in the Morrowind expansions), perform lichdom by being very magically gifted, and temporarily placing their soul in an object. Once the body dies, the soul is returned to the now dead body. In essence, becoming a lich is almost like self enchanting your soul.

The Dragon Priests are liches at this point, but were not always liches to begin with.

Also UESP is bad for lore, but great for gameplay. If you want lore, stick to primary sources, the games themselves, and http://www.imperial-library.info/.

Vamp fans LOL, Lich just rain fire over them.

I think defining 'power' might help you in your quest to decide a victor. Both have their niches.

Lich I think. All the benefits of undeath with none of the huge drawbacks like sun damage or needing to feed. Plus, they're normally powerful Necromancers so they could command lesser undead like vampires with ease.

Vampires are not lesser undead there the second strongest next to liches themselves real lesser undead are wraiths and zombies.