grave Titan and nim deathmantle attach nim deathmantle to grave Titan also. Also endless ranks of the dead, army of the damned and call to the grave. These cards help you build your army quickly and can end the game quickly especially if you have 1-2 cemetery reaper's out. call to the grave helps eliminate your opponents creatures as well. Take a look at my zombie I gestation deck posted in this forum. I have had a lot of fun playing it. But all in all you have a decent deck there.
Well, I don't like ghoulraiser ether. It is a 2/2 creature for three mana (not a good sign) and it relies on your creatures dying to get value. Think for a moment, what else can you do for three mana that gets more value? (hint: dismember)