I don't think I have one. All the developers I used to have a lot of esteem for are now either out of business or just not any good anymore.

I guess in order for a studio to make me a fan, they'd have to have a consistent track record of making great games in my pet genres. My pet genres are fairly out of fashion even among indies, and most of the good games I've played in recent memory have been from fairly new developers, meaning that they don't have a large enough catalogue to qualify as a favorite.

I guess there are a few developers who would have my attention (briefly, at least) if they announced a new game. Basilisk and Crazy Viking come to mind.

Thanks to Wasteland 2, it has to be inXile. And a slight nod to CD Projekt. I so miss the guys at Black Isle studios, but hopefully Obsidian will introduce some new great gaming memories.

I like Daedalic and Wadjet Eye's adventures. I think their games feel very close to the style of 90s point and clicks.

CD-Projekt for already mentioned reasons.

Arkane Studios for Dishonored, which made me more pleased with a AAA title than I have been in a long time.

Paradox for all the interesting stuff they publish.

Bohemia Interactive for the ArmA series and Take On Mars.

Chucklefish and Hoppo for Starbound and Risk of Rain respectively, the latter which ended up being one of my surprise favorites this year.

Soldak for their neat "ARPGs built on top of world-sims".

Spiderweb Software for all those years of RPGs

Squad for Kerbal Space Program.

Arcen Games for AI War: Fleet Command, Tidalis, Skyward Collapse, and Bionic Dues. I really like them despite the wildly varying and inconsistent quality of their games. Sometimes they turn out awesome (AI War: Fleet Command, Tidalis, Skyward Collapse, Bionic Dues), sometimes they turn out awful (A Valley Without Wind 1 and 2, Shattered Haven), but either way they always come out very interesting.

I usually end up buying almost everything Arcen makes. Even if they make something I don't like they tend to end up making something do like shortly afterwards anyway, and in any case I'll always have something interesting to talk about either way.

Not fan, but I like and respect a lot: InXile, Wadjet Eye's, CD-Projekt and Firaxis

My first thought upon reading the title - Obsidian
My second thought - CD Projekt Red
My third thought - I miss the old Monolith. Everything between Blood and F.E.A.R.

Rockstar, Dice, Infinity ward, Square E, Bioware BEFORE they turned into money greedy bastards who charge you for in game items, introduced micro transaction and day one DLC's. Though I don't know if they are at fault or the publishers.

Current devs I like

CDRed off course (don't want to get banned :p)
Remedy games (too bad they to Microsoft)
Obsidian (well because of their paste history)
Valve
Eidos Interactive
Frogwares
Monolith (though they are pretty much dead nowadays)
Red Thread Games/Funcom

CD Projekt RED
Bioware
Frogwares

:)
Nearly forgot Piranha Bytes!

Rocksteady Studios (batman games)
Arkane Studios (Dishonored)
Obsidian
Ubisoft Montreal (and this will not make me popular ;-) )

We-ell, given the number of favourite developers/publishers that have gone from "I wuv you! Take all my money! All of it! I can live on the crap I find in the dumpster!" to "what the... GET THAT CHAINSAW AWAY FROM MY TESTICLES!", I'm somewhat reluctant to offer any form of wholehearted joy at any of them, through fear of gross disappointment.

With that being said, I am happy to see CD Projeckt RED making games that I want to play, and releasing them in a form that makes me want to give them my money on day one.

Also, I'm really enjoying the output from Platinum Games. Yes, they're console-only, but Bayonetta is extremely fun, Vanquish is shaping up to be just my sort of military sci-fi thang, and The Wonderful 101 has thus far been hilarious. Very much looking forward to Bayonetta 2, and... well, whatever else they release, really :-)

CD Project Red. Double Fine Productions. General Arcade. Interceptor Entertainment. Flying Wild Hog. Valve. id Software(hopefully...)

Double Fine
Obsidian
Wadjet Eye
Derek Yu/Mossmouth
Locomalito

I really like CD Projekt RED, From Software, and Valve when they actually make games.

I approve of From Software's approach to difficulty, accessibility, and storytelling. And the fact that they owned up to the fact that the PC port of Dark Souls was not as great as it should have been gets them more respect from me. I just hope Dark Souls II has more customization options, and is a better PC version overall, as they've promised.

Hard for me to pick one (surprise, surprise) so here is a list of a few I really enjoy:

CD Projeckt RED
Daedalic
Double Fine
inXile
Wadjet Eye Games (Dave's games have such a fantastic Lucas Arts feel to them)
Larian
Atlus
Big Finish Games
Phoenix Online Studios (c'mon part 5 to The Silver Lining!!! :D)
Spiderweb
Focus

Honourable mentions going to Sierra, and Lucas Arts in their hay day. :D

I'd hate to say it, but Nintendo. Seriously, they have had some amazing first party games for the 3ds and Wii U. Of course, CD projekt. If they would just release some more news about Cyberpunk and The Wild Hunt.