as you have not defined what "successful" means in this context nor given any limitations to what "multiplayer" means...

fat princess.
uncharted 3
dark souls
little big planet
killzone 2
mario kart
smash bros
bloom blox
wii sports

Im pretty sure successful is pretty self explanatory.  successful is how well the game sold as well as critic reviews

COD 1, World at War, MW2, Black Ops, MW3 and Black Ops 2. Great thread, moving on now.

Wii sports

Street FIghter 4

nsmbw

Rockband

I agree with the OP,except for resistance. I think the multiplayer was okay successful wise,but nothing mind blowing. I think you should replace that with madden,then you'd have my list.

lol I wanted to see what came to peoples minds first.  Surprised to see Fat Princess pop up on any list though as well as Demon's Souls becuase it's not why it sold well.  Not a fan of this list at all

i agree with you.  i dont like resistance but the multiplayer was always praised as well as they always sell a couple million copies although I dont know about the third one

Call of Duty 4 -> Would still be playable today if it wasn't overrun by hackers, that's how good it is. Too bad the best game by far in the series has no post-launch support at all, and just one map pack. Plus it's the only CoD game to be more popular still than its successor (I'm like 90% sure this is true)... i.e. that it was more played than World at War during world at war's life.

Goldeneye, LoL, WoW?