First of all, play the game as you want, and have fun with it.
Between single target damage and talent points, blood has actually done the worst damage output for me. I cannot really comment much on deep frost or that dw talent build, just blood and unholy. I had gone the cookie cutter build of 51/13/7, i had a blast with it. I was pretty well geared out. After doing single mob bosses, i.e., VOA, I began to see unholy death knights in lesser gear out damage me. I would armory them and see they were unholy. After really looking at the damage meter I saw where unholy really shines, both in aoe and single target.
Deep blood will see some really nice numbers, I am not going to lie. The issue about blood is that I would have about three, maybe four really damaging abilities by the end of the fight. The numbers would generally put heart strike, melee, then either obliterate, or death coil as the main damage dealers. I mean, huge number totals. Unholy would not have as many huge number totals, but more smaller ones that in the end would total more than my combined damage. Unholy gains so much more from things like necrosis, blood-caked blade, a perma pet, and most importantly crypt fever and wandering plague. Those last two make up a huge chunk of damage potential. With three points in it, you are looking at disease damage increasing by 30%. I also cannot forget another huge, often overlooked, damage dealer, unholy blight. Yes, I know a lot of people don't care for it and don't think it is all that hot. Even on a single mob when you combine unholy blight with impurity, you will be doing a lot of extra damage for free. As soon as it expires, I always put it back on. Since going mainly unholy, my dps has shot up overall, and against single mobs. Blood just does not have enough to catch up to it.