Battlefield: Bad Company 2 should be played: in Rush Mode.
... Yep, that's it. But, we recognize that some people just like to do things incorrectly and, lucky for them, so does developer DICE. Cue: VIP Map Pack 3. The latest free download for all VIP members adds maps to Squad Rush and Squad Deathmatch -- specifically, Laguna Alta will become available in Squad Rush mode and Nelson Bay will become available in Squad Deathmatch.
Planet Battlefield was kind enough to point out the DLC that, as you can see above, is visible in the Battlefield: Bad Company 2 store. We'll let you know when you can download it.
Update: Added clarification of source and removed the "sometime in April" quote, which never originated from DICE. Joystiq apologizes for the confusion and regrets the error.