And yes, one of them is frost. No, deep frost does not cater well to leveling on it's own, as it does not have the self-sustainability required to chain pull, as blood or 17blood/xx unholy. To get the real juicy stuff in frost, you really have to go all the way down the tree, so this lends itself to an unfriendly talent tree for leveling and grinding.
Frost has some amazing control and burst abilities, as you will see in the videos comments. It will have some incredible use in group pvp. Imagine being able to instantly cast an AOE Freezing trap on everyone around you, that lasts for 10 seconds in pvp, and 26 in PVE. It's ridiculously good, especially when you remember that you can bloodboil off any diseases that may have otherwise interrupted the freeze effect. How awesome is it that our AOE taunt also has a PvP use? Major kudos there!
Also, I got a little frustrated with the slower pace of frost grinding (which is really a spec for group situations, and not solo), so I respecced back to 56 points in blood and took out my aggression on a host of mobs in the bone wastes. I won't say much more, but I think you'll be very pleased with how DKs are performing.