Leveling/solo spec

Just returned to the game about a month ago, been playing my priest, decided to level this guy as well.

I've heard conflicting advice regarding leveling/sol specs. Theorycrafting this (and experimenting just a little), it seems to me that blood may actually be the way to go - lower single target dps, but the increased survivability makes routine multi-mob pulls viable, and you end up killing 3-4 mobs in just a little more than the time it would take to kill a single mob.

Does this make sense?
The common wisdom is to level the spec you want to use at 85 so you can be introduced to all the abilities and arrange the buttons in an organic manner and such.

So, if you want to tank the dk, level him as blood. If you want to dps the dk, level as frost or unholy.

That all said, if you just after faster leveling, it is true that survivability is better than dps. While it takes longer to kill mobs, you more than make up for it by not needing to find your way back to your body and rez after dying.
I definitely recommend blood.

I do frost in bg's and occasionally dps dungeons, but as blood you can pull 3-4 mobs and just heartstrike them down quicker than you could as frost.

Frost single target is better, but pulling 3-4 mobs as frost would cause you way too much downtime, and blood has ended up being much faster for me.

Instant queue tank dungeons are a plus.
In Wrath you hit a lot of ellites and multiple mobs, blood is great most of the time.

Once you hit Cataclysm you are not going to be fighting more than three mobs at a time and you are not going to see an ellite unless the quest giver gave you a pet to help. This means go frost, you will mow through single mobs and multiple mobs only take a couple more seconds. Dropping into blood presence will drive you mad; before going frost you'll tell yourself blood kills fast enough, but once you get frost down blood killing will feel like molases.

Bottom line: go frost for cataclysm where survivability isn't an issue.
Been leveling this guy as blood. Its stupid easy questing or rolling through dungeons.