I've played every version of Command & Conquer.  I LOVED every one except the one they turned into a 1st person shooter.  Now I'm hooked on the online version "Tiberium Alliances".  More after the jump.

Tiberium Alliances

Tiberium Alliances is a "browser" game meaning there is little to no download. It's in the category of what is called a "tower defense" game.  It's also FREE to play.  Of course you can pay a little and advance a little quicker through the game and it's upgrades. You build your army, defend your base and destroy other bases.  Fortunately most of the other bases you're destroying belong to a race called "the Forgotten"; this gives players a chance to build up and do something other than constantly destroy each other.  The ultimate goal of the game is to team up with other players and capture the middle of the map.  The game is simple to get involved in and once again free.  You can check it out here.  I don't know if you can join my actual game, but if you want to try I'm on the "World 39" server. I have two accounts "Nessmania" and "Nesstopia".  I'm over in the West/South West.