RTS game suggestions

Hey guys. I'm getting back into PC gaming after being mostly a console gamer since I was a child, and only really play the odd PC game. I'm looking at getting World In Conflict or Company of Heroes so I have a couple of questions. I've played a little bit of the single player for both of these games so I'm mostly after online advice.

1. Which game has better online multiplayer?
2. Which game has more people playing(also the amount of people playing for each would be nice)?
3. I'm not the best at the RTS genre so which game do you think would be better for me while playing others(I am a pretty quick learner)?
4. How many expansions to each of these games have and will I actually need the expansions?
5. Which games multiplayer tends to last longer without getting boring. By this I mean how long would roughly be able to play the game without getting bored. Basically value for money(for example starcraft has stayed fun for many years)?
6. Anything else you would like to add?
7. If you think there is any other RTS games I should consider(also answer questions 1 - 6 if you could)?

Thanks

I'd say you get COH I only play it for the MP. Single players still fun but its all about the MP. There are 3 games in total. If you get a copy of tales of valor you get all 4 armies just not the 3 extra single player camp. Best MP game I've played since starcraft. COH is also scored higher by the users/reviewer base.

Thanks guys. I did enjoy the single player of CoH more, but I am mostly after multiplayer. Sp if you say the multiplayer on CoH is still tops I might grab that.

Aplastic spoon I don't really have the issue with my system not being able to run a game, I do game on a laptop mostly, but it's pretty powerful and runs most games very well. I have red alert 3, and I used to have Red Alert and Red Alert 2. Basically I've played quite a few RTS games(although I'm not that good lol) because that is a genre the PC does significantly better than the consoles.