My apologies, when I said released I meant released for public testing / playing (ie, it's current state).
I've played a little with keyboard and mouse as well as a controller (using community settings) and currently it very much feels like it would be difficult to play with a controller (I'd like to stress I'm hoping and happy to be proven wrong about that further down the line).
My surprise was that Valve have brought about a game like Deadlock which currently (to me) feels very much like a keyboard and mouse only game. Again, looking forward to that potentially changing.
Nice post OP, a few of mine off the top of my head;
Half-Life (+expansions + Black Mesa)
Bioshock
Deus Ex
Call of Duty: Black Ops (World at War was great too + ZOMBIES!)
Morrowind / Oblivion / Skyrim
Fallout: New Vegas (+DLC)
System Shock 2
I played a few of the MoH (I can't recall which) but never owned them.