Vampires shouldn't feel like humans with a few weaknesses and a few strengths there should be aesthetic changes and sever play changes. Feeding should make you stronger, not weaker. And in your final stage you should look like this.

http://www.google.com/imgres?num=10&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&biw=956&bih=403&tbm=isch&tbnid=TEd7zSDc1IzC2M:&imgrefurl=http://www.turbo-exp.com/2011/06/review-priest-guest-post-by-stephen.html&docid=z8T29kjsQBowxM&imgurl=http://2.bp.blogspot.com/-sSr7DZiGrgs/TfVk35I-nPI/AAAAAAAAB_A/92B-zJbg160/s1600/priest-review-vampires.png&w=536&h=350&ei=LLH4TrKEB8bk4QTe8vmcCw&zoom=1&iact=hc&vpx=441&vpy=109&dur=10299&hovh=181&hovw=278&tx=174&ty=116&sig=101649911882957366569&sqi=2&page=1&tbnh=92&tbnw=123&start=0&ndsp=12&ved=1t:429,r:3,s:0

And not be able to wield normal weapons or wear normal armor. You should pounce on your prey be immensely strong and be able to feed off any human (asleep or otherwise) and infect or kill them. You would have to feed a lot to get to this stage and at this point sun would kill you in a few seconds. Things should be fairly normal at earlier stages though increased strength and ugliness would appear. And at the very earliest stage if you wear a hood and its night you can pass for human as long as people don't look at you for to long.
Also add some poison known as essence of garlic or something and allow certain holy weapons a bonus.

When the moon hits your eyes like a big pizza pie that's amore....
Hello anyone?

I actually like the whole feeding offsets vampirism thing. Blood is like a medicine. THe most powerful vampires you see in the game are far away from civilization.

No. They should be Ice Vampires, who sleep in frozen lakes.

should they sparkle like edward cullen?? or shine like voldermort??

Since when was Voldemort a vampire? Since when did he shine? Maybe he does shine, but I've never noticed it :/

There are countless different interpretations in fiction of what vampires are, how they behave, how they look etc.
No two people are going to completely agree on definitive traits for vamps, look at the vampire in fiction... how many different versions (including the Twilight twinkles) do we have now?

Thousands.

These are Skyrim vampires, not the same as your Blade vampires or your twilight vampires or your Buffy vampires.
Not the same as your Dusk 'till Dawn vampires, different from your Legacy of Cain vamps, different from your Vampire: The Masquerade bloodsvckers.

You can say you prefer this kind of vamp or that style of vamp but to say "vampires in Skyrim should be like this..." is wrong imo.
It indicates that your interpretation of vampire is somehow "correct" and the games interpretation somehow incorrect, which is simply silly.

guess you've never come across voldermorts reply to the twilight fans then

There's already 3 books in TES that cover vampires. One of which mentions the Volkihar specifically, and they are not the same as the Cyrodiilic bloodline.