In order of company I respect:
Nintendo
Sony

Microsoft.

In order of companies I support:
Sony
Microsoft
Ninetendo

I have a Sony TV, and a PS3. I have a 360, and a Windows PC (but I didn't pay for any of the software, as my company bought me an MSDN license.)

I have not given Nintendo a dime in 10 years, mostly because I don't like the games. It's just not my style. Sony seems to do the best job at making high quality consumer electronics. I have yet to be disappointed in anything of there's I have bought.

That being said, I am a die hard capitalist. If an of those companies makes a product that's better then the other, that's what I buy. I have absolutely no bran loyalty (as they hold no loyalty for me, why should I for them).

That's why my house is is a hodgepodge of every electronics company from Sony, MS, Dell, Apple, Motorola, AMD, Intel, ATI, Nvidia, Denon, Polk, and a few others.

Sony......they've proven themselves over the past 12 years, whereas I believe that Nintendo is stuck in 1993 (I really don't want to play Mario Kart/Golf/Party anymore). And Microsoft....people are only jumping to their ship because they're on the come up with the early success of the 360, but those same people seem to have forgot the original Xbox. The original PS was great, the PS2 is STILL great, and the PS3 will be great. Enough said

microsoft for me it has the best online right now, but will have a battle with sony down the road for this title and has halo, ninja gaiden, fable

Nintendo because of their games and innovations to the industry.

Sony and Nintendo roughly equally. Both have large in-house development teams that make buying either company's consoles worth it.

Nintendo has EAD 1-3, Retro, HAL, Intelligent Systems, etc.

Sony has Naughty Dog, Team ICO, Insomniac, Incognito, Sony Santa Monica, etc. 

Nintendo
they make my favorite games

Nintendo.

1. Because it is purely a gaming company unlike Sony and MS, and it understands the market better than anyone at the moment.

2. Because it is the underdog and I tend to support the underdog. : )

"Sony......they've proven themselves over the past 12 years, whereas I believe that Nintendo is stuck in 1993 (I really don't want to play Mario Kart/Golf/Party anymore). And Microsoft....people are only jumping to their ship because they're on the come up with the early success of the 360, but those same people seem to have forgot the original Xbox. The original PS was great, the PS2 is STILL great, and the PS3 will be great. Enough said" - BMAKER11 ditto

@JBoogie: I'm not flaming you here, but you asked us for valid points and then didn't make any rofl.

I love Nintendo the best, because of their philosophy about gaming. Their main games (ie the Mario platformers, not the Mario Sports) are filled to the brim with a sense of wonder, exploration, and childlike glee. They are endlessly inventive, and they always reward you for going off the beaten path. You might find a secret room with a 1up, or a missile expansion, a piece of heart, extra Pikmin, it's all the same feeling.

Also, they are not using the gaming industry as a trojan horse for their other ulterior motives (Sony and MS have devices that 'plays good games, too!'). They just focus on the sheer fun factor of video games.

Having been a gamer for nearly 25 years, I (desperately) look for anything which seems different ...
As such I favour Nintendo's approach