In all honesty, if you want to enjoy Halo 3 right now then just play Rumble Pit. It has zombies, slayer and a decent population. You'll also play on the DLC more frequently then other playlists. Big Team Battle also has a decent sized community. Other playlists are just completely different than how they used to be in terms of population and competitive play. MLG is good if you can find a game without derankers. The problem is with Halo 3 there's a lot of mexican hosts, bad connection in general, and cheaters.