But if you're a lich you are dead... Properly dead... EVERYONE will attack you on sight style...
With a werebeastie you're 'normal' most of the time.
With a vampire you can be kinda 'normal' all of the time.
With a lich you're a lump of decomposing flesh with a very bad reputation... It would be cool but I feel it wouldn't work too well in practise.
Actually, as far as aesthetics go, Vampires and Liches are just as recognisable. Both ugly. Oblivion's Vampires blended in, because that was the clan of Vampire in Cyrodiil. Daggerfall and Morrowind both had permanently ugly characters.
I'm pretty sure the only other vampires that can blend in are:
The Bonsamu: Appear to be normal in normal circumstances, but the moment candlelight (and I assume any kind of fire) hits thier face, you'll see them for what they are. This means that the obviously can't venture in the daytime, but at night they have to steer clear of civilisation, as there are candlelights and torches everywhere. Unless they sneak/stay away from people/hide thier face.
The Keerilth: I'm assuming they're ugly usually, as there's no mention of it, and they can take a mist form. They hide by "possessing" children and posing as them for years. I doubt we'd actually see this because of how squeemish everyone is over children.
Both of these are native to Valenwood. We'll (hopefully) actually see the Skyrim specific clan, the Volkihar. They drag victims under the water through sheets of ice. Rather impressive, if I do say so myself. I'm intrigued to see how they handle it.
But yeah, I doubt we'll be able to blend in so easily. Gets kinda old to have pretty much the same vampires in each game. And they have such great lore ready for them.