I would us Blood any day for leveling, without a doubt. I have seen a leveling build posted by somone on the first page... it's decent but lacks important levleing tallents. You are all reading too much EJ threads about raiding on a DK.
When I leveled my toon I surely used Vendetta because killing a pack of mobs was healing me like crazy, also I think I used Butchery. I simply had alot of trouble trying to get killed.
You dont have to get all formal and shit and only put points in 2 trees, pick nice talents from all, like Improved Icy Touch to slow down the attack speed of your mobs. Also, I would not use Obliterate and pick up DnD glyph instead... DS and HS is all you need as main damage dealers.
Using a perma ghoul without the glyph is preaty much useles, I remember him dieng very easy in these conditions.
Blood was fun to play, I was doing 3-men quests alone, burning booldowns, and finishing with over 75% hp. Packs of regulars mobs were killed with a remaining 90%+ hp, almost never using a bandage, and also never using a pot because of Improved Rune Tap. Using Improved Blood Prsesnnce also helps self healing alot.