If I should decide based on my tastes and what catered best for them, I'd say USA and Japan during the first generations and coin-op times, then, since Doom, Ultima Underworld, Syndicate, Gobliiins and Lemmings (to name the oldest greatest ones I can remember I used to play when I started gaming on PC when I didn't even own one) times, Europe and USA. I guess for those that stayed on consoles Japan kept a higher ranking longer and could still keep it.

Edit: the whole North America and not just USA makes the region stronger also for my tastes, but it doesn't change my rankings, since Europe became strong in game development it had some sad SW house deaths through the years, but it remained very strong.

Depends what you want to play. Overall I'd say the best talent is European.

GTA

Batman Arkham

DIRT

Littlebigplanet

Rayman

DmC

Minecraft

Killzone

Horizon 

Witcher

Heavy Rain

Worms

Far Cry

Elite

World of Tanks

EVE

Dishonoured

Battlefield

A few of the many European games. Though many people often assume European games are American. It did get harder with publishers such as UbiSoft having studios outside of Europe too.

Europe's importance to videogames is often overlooked because it was such a separate ecosystem until the PS1.

Battlefield was made in Europe ;)

DICE are European.

Japan followed by North America.

This question should come with an example list of games for each region.  I just voted NA assuming that many european games were from there (I probably would have voted NA anyway, but still).  

People are putting UK together with Europe, I don`t know if this is accurate at all. UK seems to be it`s own thing, some british people I know don`t consider themselves Europeans.

They are about equal nowadays, but up until a few years ago I thught the Japanese made better games.

Probably Japan with Nintendo, Square Enix, From Software and maybe Atlus/SEGA if you consider their games to be AAA?

Europe, its funny reading through this thread the ignorance from other continents that don't realise how much Europe make and think it's their Own continent that make those great games.

Alright, I see your point...