Ugh, I hate C&C Multiplayer....

[naut]

That sucks that you had such a bad experience, I guess their online community is not refined.

Age of Empires III

Any Age of Empires is pretty fun online.

Act of War

Thanks for the tip.

Battlefield 2

Battlefield 1942 is the best.

Battlefield 2142

It actually contains spyware in it.

Dawn of War

Yeah, not bad.

Warcraft 3 FT

I hate the real game, only maps like DotA make it fun.

For a good FPS, try ...

A few that have impressed me:

Call of Duty or Call of Duty 2, they're just great.
Castle Wolfenstein, has pretty impressive multiplayer.
Call of Duty 3, pretty much a copy of Castle Wolfenstein's multiplayer. However, only if you have an XBOX 360.