I hate halo because its just a bit retarded all over, with bright coloured armor and jumping a metre and a half in the air, it all seems a bit 'my first shooter' to me.
As for CoD, I don't hate the multiplayer, actually I really enjoy it. I'm just not fast enough for online mp, since I'm practically using dial-up XD. I reckon I enjoy the feel of an in-your-face discrace that splitscreen allows ;P
As for other games I play online, I've been addicted to Killzone 2's mp for ages, every time I boot it up I look at the clock and it's five hours later XD.
I also play Battlefield Bad Company, it's good fun ;P