Of course there is no wrong answers here. I am just curious to know who you think is the best dev team in gaming and why you think that way.

I feel Team ICO is the best at the moment. They do not make games that sell bucketloads and oddly I guess they wouldn't be considered "Powerful developers", but I think in terms of art in gaming and the ability to tell an excellent story Team ICO stands tall above the rest.

Naughty dog.

These days, I say Atlus. No other games make me as involved in them.

PD

Their game has ruled its genre for over a decade, its is beloved by the car industry and automotive enthusiasts.  High quality and great sales.

Naughty Dog

Infinity Ward.

Call of Duty: Modern Warfare was superb, and I expect nothing less from Modern Warfare 2. Few developers manage to create such a well crafted singleplayer, and that alone makes this Infinity Ward for me (subject to change as time passes by of course ).

I'm going to go with Cing. The few games they've made have been very well put together with excellent writing, resulting in titles which are totally engrossing from start to finish. Not the mention the genres they tackle are somewhat under-represented.

I can't decide between Atlus and Team Ico. So I won't, and you can't make me.

Valve. Every single one of they're games has been amazing and revolutionary. Half-Life, Counter-Strike, TF2, Portal, Left 4 Dead...they have a pedigree like no other.

Atlus is one my top choices as well. I love almost anything released by them.