I've yet to see any AI impress me, including HL2. To be honest, i don't really expect much in the way of AI when it comes to games, when it all comes down to it, it's all hide behind rock or open door. Now, when it comes to locking a door on an enemy, only to have an enemy run off, phone a hire company, rent a bulldozer, wait for delivery, get in said bulldozer and knock down the building you're in, THEN i'll be impressed.
Half-Life 2, Farcry, Halo 2, Doom 3, infact, anything with any shred of AI, i've not been impressed by a single one, but then again, if you're just playing games to bitch about the AI, maybe you should stop playing games.
But as an exception to the above statement, if it's something really retarded, as my teammate in Halo 2 who spent 5 minutes driving around in circles because he obviously didn't know how to stop the warthog, sometimes the AS (Actual Stupidity) stands out a little more than the AI.