I'm finding the necessity of a console to fulfill one's gaming habits to be waning as time progresses. With the exception of a few console-exclusive titles, there is a siginificantly larger PC game library to choose from (since essentially ALL PCs are backwards compatible), and the PC itself is far more versatile than a console. Granted, the console makes for easier access to certain entertainment functions, with a little bit of tinkering, you can do the same with your PC. The only advantages consoles have over PCs are that they have massive backing from their manufacturers (I've never seen Microsoft pushing PC product like they do with their console), and they tend to get first/exclusive access to some of the bigger AAA title being made out there (which doesn't make sense to me, since exclusivity limits your market share. The benefits of "converting" people from one console to another is minimal, and just releasing it for all systems would make more sense, from a profit perspective).
With all that being said, I own a 360. The PS3 has had trouble from the very beginning to turn a profit and really stand out in the market for something other than a game console over the past few years. They (Sony) had the advantage when first it launched because of the built-in Blu-Ray, but now they're so cheap that it doesn't make much sense to buy a PS3 for 1/3rd more the cost of a decent Blu-Ray player. Microsfoot has an advantage because they've got product already in the household (PCs) and are integrating their console to work with your computer to stream content throughout your house from either the PC or 360. Kinect also helps them, only slightly.
Why you don't even mention Nintendo in this thread baffles me and also disappoints me.