Love: Obsidian's writing staff.
Hate: Everyone else at Obsidian.
And I guess Valve. (Bear with me hippies!) I love all their games, but they need to get someone else in charge of releasing content. TF2 has been flooded with so much garbage by this point it's just not all that fun anymore, and L4D2 is in serious need of new content. And not just one fan made campaign after 6 months of dead time.