Today, EA/Dice announced Battlefield: Bad Company 2, a sequel to the first (being released on PC as well!) and Battlefield 1943, a throwback to the original using the Frostbite engine that powered Bad Company and is said to power Battlefield 3. It contains 3 of the most popular maps and is aimed to be a low-price game.
So that puts the count of current Battlefield games in the works at 4.
Battlefield: Bad Company 2 (PC, 360, PS3)
Battlefield 1943 (PC, 360, PS3)
Battlefield Heroes (PC)
Battlefield 3 (PC, unkown)
Which are you most looking forward to?
EDIT: And I don't think I'm going to vote. Being the crazed Battlefield fan I am, I want them all.