If you want your undead to be as beefy as possible you should take Corpsecrafter. There is another way of getting +2HP/level apart from Desecrate with shrine, but I don't remember it, so technically the max HP/HD you could get are D12+8.
I find the bigger your undead the better Corpsecrafter gets, so it's not a low-level feat. +40HP on a 20HD critter are quite important, IMHO.