Sony: Minor negative passion
MS: Significant negative passion
Nintendo: Infinite negative passion
Valve: Neutral
Blizzard: Slight positive
2004 and earlier Nintendo: passionate

I primarily game on Sony consoles and PC.
I play strategy/WRPGS/FPS on PC and everything else on PS3/Vita including some exclusive FPS games.

I'm overall happy with what I get from Sony 1st party and they continue to get great 3rd party support (PS3).
I love specific genres on PC and there are some experiences which can't be replicated on consoles IMHO.

I love Microsoft for PC only (Win7). Hate their policy on pay to play online (360).
Neutral about Nintendo as they are going out of their way to not appeal to me (Casual and non mature games).

Slightly positive about Valve.
Love Good old games. (www.gog.com)

Used to be a huge fan of Blizzard and I still love their starcraft series but I lost a lot of faith in them after the clusterf**k that was Diablo 3.

edit- My first console was the Sega MegaDrive/Genesis and I loved it. I then made the switch to the PS1 and have stayed on  with Sony consoles ever since. Although I have been seriously tempted by the 360 and have also owned an X-box in the past. Loved a game called Sudeki on it :) .

I would argue I am more passionate towards Sony, but I am a Nintendo gamer ironically...

Mainly because as it is now, I look at Sony to be the industry leader. Maybe it'll change in the future. But for now, if they innovate, make mistakes, it sets the record for everyone else. Don't do this. Or aspire to this! Their ability to gather large and diverse amounts of third party support for example.

Kinda like with Squeenix, they were so loved and adored, but now they get trashed harder than other companies for not being as great anymore. They are not producing the mega hits anymore and there is so much criticism.... Even though the games they release, if they were released by another company without the preconceptions, would be considered "great" and decent games in their own right. Most of their games would probably be better appreciated otherwise... that's how I 'temper' my passion.

I also expect Sony to have the most diverse lineup... so for me, Sony is the company to compare... I have to be careful how I criticize, because sometimes I get so mad about bad decisions in the industry, I kinda want Sony's ass on a platter because I don't want other companies to copy their bad decisions. I feel like it reflects badly on the industry as a whole... especially the $600 price tag of the PS3 initially. That decision made my blood boil because I like to adopt closer to launch than later. But I had bills to pay...

So, it's only because I put Sony on a higher pedestal than others that there is more 'passion' persay. You know, without the preconceptions and high expectations, I think Sony would get more people taking a risk... the games they release are actually good. It doesn't reach the penacle of PSX/PS2 to me. But on it's own, it's a good investment to buy Sony. Besides the higher pricetag and the stupid memory card prices of the vita for example!... it doesn't deserve the hate, based on the quality. They've made a mistake with their pricing practices... that is all.

With Nintendo, I give a pass. And you know, I think they take advantage of the pass they get by people like me. They obviously have to survive. Certainly they are wiser in some ways. They are not #1, but they are steady in the quality they produce for the most part and if there is a void tobe filled that the other companies don't fill (children's quality games for example), Nintendo caters to the lowest common denominator. They also have the obvious cash cows they've rode hard since the NES days. It's harder for them to be the object of criticism because they've set the bar so damn low... I mean really, Sony sticks it's head way out there and gets whacked. Nintendo makes silly decisions, like making the Wii without HD at a time when we're deciding between bluray and high definition DVD, and yet here we are, Wii 2... still great to be a Nintendo gamer. However I think with Wii and Wii U, they've tried to be more of risk takers... nobody knew that motion would take off like it did. Maybe the gamepad screen will eventually catch up somewhat...

Nintendo tends to try befriend the 'niche' market in the gamers too... we are also satisfied, so that improves word of mouth for them... even though sometimes it's the the same stuff over and over. (Pokemon, Harvest moon, etc) I think everyone always owns a Nintendo console to play their first party, it's just kinda a given. The niche is a bonus. Nintendo plays their strenghts well. Nintendo gives me a happy glow, but I don't really feel like I am 'passionate'. If they mess up, I will probably smirk, but I think I would be less hard on them than Sony... which isn't really fair and is probably unreasonable.

Xbox, I've never owned, so I can't say one way or another. I played a little of the first one and thought the load times were horrible and didn't like the way games were accessed, things of that nature. Probably because to me it was too much change LOL. The controller I remember not liking. I tried the 360 one again today and my hands seem too small for it. Besides that, haven't felt compelled to care too much about it. I've been tempted by the 360 more than once, but so many of the games on are only ones my husband would play and he has those on PC. I don't play shooters, so I don't really care too much. They don't cater the genres I play one way or another... and it doesn't have bluray and I know I would like bluray eventually.

Besides that, I temper my passion, because some of it is reactionary, not reasonable... I try to just buy and invest in what I think is fun and worth my money. I may own a Nintendo, but still like Sony better for their system... but I think Nintendo has more of the genres I play. I look forward to PS4.. hopefully things will change for the better. Not that PS3 is bad. It just didn't sell to me.

Edit: Only other company I've been passionate about is Sega, but not enough to sell it to other people. I owned Dreamcast, mostly for Sonic. We know what's happened to him since then... after that, I just play what looks fun :( I get mad sometimes that Sega failed where other companies thrived, but it's not like it's anyone but sega's fault...

I bet there are a lot of people who don't know what link is. I know it only because the link training crossbow game.

The last time I was passionate about a console company was SEGA and I have learned my lesson.