I've started to get back into CoD4 after a month or two hiatus. The Hardcore Deathmatch mode is a lot of fun. No hud, more weapon damage, wait times before respawns... It's way better than the regular gameplay mode.
And as much as I wanted to love Halo 3 and play it as much as I played Halo 2 (which was a LOT), too many little things conspired against me. For one, the melee system is broken and just frustrating as hell. That said, I think my #2 weapon of killing is melee so maybe I don't have too much of a right to complain. The levels also really suck compared to Halo 2's, Bungie can throw all their fancy map testing they want but very few Halo 3 maps have matched awesome Halo 2 levels like Ascension or Lockout. Halo 3's Narrows might be the worst Halo map of all time.