Best: I'll have to go with Mass Effect, wish there was a multiplayer feature, though; or Freespace 2, absolutely best story driven game I've ever played, bought it 10 years ago, and still play it now and then
Worst: Heroes of Might and Magic for PS2, played it a whopping 1 hour; worst $30 I ever spent.
BEST: COD4 without a doubt
WORST: Vietcong, a lot of it was good but there were levels through pitch black tunnels which i had no idea how to beat without cheats. Ruined the game for me.
OTHER THOUGHTS: Far Cry 2 is really fun except for spending most of your time traveling all the way across the map to do different missions. I have stopped playing it even though I'm only 12% finished. I might have to try that teleport mod you speak of ducis