Keep it civilized, respect others' opinions and give reasons.

I only included HW manufacturers in the poll, but you can talk about developers or publishers too.

For me:

Hardware

I like MS the least. They don't have much I'm interested in basically, not a big fan of shooters usually, and paying to play online is a big no-no. I dislike the emphasis they put on casual gaming and family entertainment lately.

I mainly like PS products as they cover my needs best, and though I'm not a fan of Nintendo I have owned some of their home and handheld consoles and I recognize that they make quality games and products. Not for me, but I can see why it's liked.

Software

I don't hold a grudge against any company. I don't think I have ever bought an Activision or THQ game though. Rockstar, and Kojima productions are probably my favourite developers.

I have a love/hate relation with Ubisoft, because they seem to support every console out there, which is worthy of praise, but they also had the recent Raymangate and the major fuck-up that was AC3, as well as DRM, etc.

How about you?

Please vote! I'm interested in seeing where allegiances lie ;p

Hm.

Well, I wouldn't say I'm a fan of Sony, exactly, but that I'm a fan of Worldwide Studios. I think they're the best collection of developers out there. I respect Sony Santa Monica and Naughty Dog immensely, along with some of the others, like Media Molecule and Guerrilla Games. By default, I guess that makes me a fan of Sony's hardware, because they make the games I like.

I wouldn't say I dislike Microsoft but I do hate their online policy. I don't believe that multi-player and video services should be behind a pay-gate. Their exclusives don't do all that much for me either.

I don't dislike Nintendo, either, I'm just kind of apathetic toward a lot of their games. Mario and platformers in general don't inspire me very much.

EA and Bethesda are both love/hate for me, almost to an extreme. EA does all these crappy schemes and weaselly things to extract more and more money, yet they're responsible for some awesome games. That's where, to me, they're much better than Activision, which has very few games that interest me. Bethesda, likewise, makes some amazing and unique games that make the industry better by existing. However, at the same time, those games are rife with bugs, a fact that doesn't seem to bother them one bit. Fallout 3, one of my favorite games ever, was filled with bugs. Fallout New Vegas, which I also loved, was filled with the exact same bugs. I mean, seriously, fix your engine.

BioWare falls under EA, but I'm gonna mention them separately, too. They're pretty impressive. Even the storyline parts of their Star Wars MMO was a lot of fun, though it turned into a bog in the end-game, like most MMOs. Cannot wait for Dragon Age 3, by the way.

I also like and support Atlus, though they make their fair share of bad games.

If there not Sega then they ain't worth shit to me.

I don't dislike any company. I do however think a certain companies fan boys seem to be worse than the others.

I really dislike Microsoft as a company, monopoly and all.

I'll probably never get a Microsoft console because I don't like shooters. (Halo is the only exception)

I hate Sony fans. I like Sony as a console maker and a hardware company, but I really hate the fans who hate Nintendo.
I had a PS2, skipped PS3. Might get PS4 if we see some more good Japanese games than PS3 had.

I like Nintendo the most because Nintendo pretty much made my childhood. Their games have much charm to them and don't rely violence and sex to sell. Puzzle action adventures and JRPGs are my favorite genres so I'll be sticking with Ninty for a while.

Had every single one of their handhelds since 1998.

It's kind of hard to look fondly at Ubisoft right now, but I still really like the creative talent there. Especially Michel Ancel, who is a genius of game design.

I have tremendous respect for Team Ico, despite the painful delays for The Last Guardian. I'm not sure if any studio has done more with only two games.

Retro Studios is another favorite of mine. Metroid Prime was such a major achievement, especially considering the huge expectations from fans.

After all these years, I still have a soft spot for Rare, even if the studio long ago lost its greatness.

Bungie, too, is great. Can't wait to see what's next from them. Although the ads on this site give me an idea :P

And, finally, Nintendo EAD. They've been making the best games on the planet for almost thirty years.

We're lucky to have so many talented people out there making games for us :)