See, the problem is you had to limit it by "that creates consoles". You end up alienating Natsume (Harvest Moon series), Atlus Software (Trauma Center: Under the Knife, Summon Night Swordcraft Story), Konami (Lost in Blue, DDR), SNK (King of Fighters series (up until it got bought out, then it kinda sucked))...
But, sticking with the tradition of "that creates consoles," Microsoft. I'm using windows. I have a windows mouse. I have a keyboard with a windows logo on it. My desktop is a windows default. My sound scheme is windows default. I'm using windows firewall....Get the picture?
Now if you limit it to "that creates consoles, but based only on their games," Microsoft loses it's lead to me, beaten by nintendo...Then again, Microsoft does have that one $200 xbox game, Steel Batallion.
I'd personaly prefer to break the rules right now, so don't expect the next line to say my favorite is Nintendo, Sony, or Microsoft (and don't expect it to be a company you even hear about in the news anymore either)...
Sega. I still remember plopping my backside down on the floor and running through loops as Sonic, or trying fruitlessly to rip the other guy's heart out as Talon in Primal Rage. Maybe throw in a little MKII here or there, but mostly Sonic 1, Sonic 2, and Sonic & Knuckles. Good times... *runs off to play some more*
(huh. That turned into more of a rant than I wanted it to >_<)