section 8 deserves a mention as it meets the intended criteria of OP. i enjoyed that game but was disappointed with GFWL and the game’s server hosting hurdles. ugly style but good gameplay!
quake team fortress had objective based maps “canal” and “town” which i played for years.
i also played both enemy territories:)
[QUOTE=Bittermetal;347802]Counter Strike. Plant the bomb escort VIP, Extraction… all game mode on early CS. the precursor to all these other objective based games.
BF2 super objective based, especially if you have a good Battle Commander giving all the squad leaders proper objectives.
BF212 Titan mode - stop opposing team from activating silos so they will not fire on your Titan. Opposite -Launch yourself on the Titan to take out the reactor and bring the Titan down.
BFBC2’s RUSH mode. Objective is to take out the M-Com stations.[/QUOTE]
bf2142 titan mode… still possibly the most FPS fun ever 
Team based objective shooters are my favorite, almost every shooter I buy falls into that catagory.
Some of my first shooters were operation flashpoint, america’s army and ghost recon games.
When those franchises went stale, I moved on to more consoleized series’.
Socom WAS one of my favorites but S4 isn’t very tactical. Killzone 2/3 were good. I played COD games a bit but only in SnD, demo, or domination… I still think they aren’t considered team based or tactical though. MAG was a big one, and of course I’ve got brink. Outside of those I still play OFP DR for xbox and battlefield games regularly… BC2 atm, waiting on BF3.
EDIT: Oh and battlefield 2 project reality, that game rocks but is too slow for many players.