Well i recently been play black ops zombies with by friends it been fun voice chatting and shouting when the zombies swamp you from behind. There is one thing i don't like about black ops zombies is that it is like impossible to "finish" unlike left for dead 2 it lacks a goal to finish or get to the end.
Black ops Multiplayer is not fun if you don't play with some RL friends. I play with my friends clan they are always online and are pretty good it is fun to play with them. Multi player isn't the best because the weapons and everything else looks pretty ugly and stuff. i personally use ak47/commando with ghost, slight of hand pro and hacker pro i am not very good at this game though.
Black ops single player had good graphics it was a fun to play through 1 time but i am not playing to play it again though.
Summary: Black ops is a good addition to my collection of games and is quite fun :)