what do you think makes good online multiplayer?

 IMO

1. options, you should allways have several modes to pick from and weapons and characthers.

2. people in a room, i know lots of people want rooms with 16/32 or more players, but i prefer smaller rooms, like GeOW's 8, this is because with fewer people, its easier to communicate and its easier to move around without being killed instantly, which allows tactics which i think is great

3. communication, the more people who have headsets the better, its much easier to co-ordinate your tactics if you can talk to your team.

these are my top 3, i like games which have 2 of them, but love games that have all 3. These mainly apply to shooters, as i rarely play non-shooters online. my favourite online is GeOW (360 version), as it meets all of my top 3! 

I agree with your top 3, and to those I will add maturity of the player base. That is why I so greatly prefer PC online gaming (most of the time) to its console counterparts.....there's so many teenage pricks that are just a pain to play with on consoles (except the Wii - but you can't really communicate with people there).

I prefer to have as many people as possible in the room.

I'd only take your number 3 if it came with epsilon's "mature player base", certainly not on it's own. I type fast anyway.

5: whether the game is StarCraft or not.

First of all I think there should be variety.....a reward system to increase replayability..

some kind of co-op...teamwork & most importantly it should be fun

Stricter rules on the language and behaviour of players.

Soooooo many times ive had to sit and listen to silly teenagers throwing out pathetic insults, it just detracts from the game. There should be bans applied and firmer rules regarding those who have headsets. I dont have one, so sitting and listening to some snotty 15 year old call me a wanker for kicking his ass is not pleasurable, and wouldnt be for him if we were in the same room