I would have to say for best strategical perk its OMA. The ability to switch from stopping power, for all all around killing power, cold blooded, going secret agent man, hardline, make sure them you get them kill streaks, danger close, for massive increase of kill streak damage and yes occasionally the noobtubage.
Now the best perk for just raw killing is sleight of hand. The aim down the sigh and quick reloading is a huge advantage in firefights and really benefits my rushing play style.
As for the worst perk scrambler, all it does is tell your enemy your coming from a mile away.
And for the most OP annoying ass perk. You guessed it: COMMANDO