Naughty Dog - ND were the first developer that I ever bought a game from because it was made by them. It was Jak & Daxter (one of my all-time favorites) and I'd been following it ever since I'd heard 'from the makers of Crash Bandicoot'. Since then they've made this generation's best trilogy and are making a game that, to quote one critic "looks so far ahead of anything else that's coming out it's not even funny".
Criterion - Criterion just don't have the term 'half-arsed' in them. They pour 100% into absolutely everything they do, be it visuals, social features, or, heck, even ports to handhelds. The generous helpings of free DLC in Burnout Paradise and invention of Autolog are just two examples of what they do for gamers and the industry.
thatgamecompany - I was on board with tgc ever since fl0w, but then they really surprised me with Flower, which is still very much the best game on PSN for my money. I spent an agonizing amount of time waiting for Journey and it didn't disappoint. These guys get it.
Retro Studios - Retro earned a rock-solid place on this list just through Metroid Prime alone. A perfect realisation of Samus' adventures in glorious 3D, they went on to make two great sequels and then one of the generation's best platformers in Donkey Kong Country Returns. No matter how rubbish the Wii U currently looks, it'll be these guys that get me to buy that system.