Well I'd say Microsoft have the most solid stuff so far, but that's to be expected with their Xbox360 launch round the corner. They have games announced, details announced, and the price has just leaked and hopefully to be confirmed (or denied) later today.
Sony (read: Ken Kutaragi) are just throwing petty and quite cringeworthy stabs at other companies around like there's no tomorrow. I don't think they realise that, unfortunately, those stabs are likely to receive more attention than the latest processor number they release. Oh dear.
And Nintendo haven't really done anything, leaving everyone to speculate if anything they do will turn out to be revolutionary or not.
Being a Nintendo fan, it's kind of annoying to say that Microsoft are probably 'winning' at the moment because they seem to be getting on with it the most. Unlike Sony or Nintendo, they're not relying on more speculation than fact.
The true war will begin when all three consoles are released into the market, consumers have 100% concrete details to play with, the software is out... etc etc.
And at the moment, I'm likely to buy the Revolution simply down to blind hope and adoration for what Nintendo puts out. That's not to say however I'm not strongly considering an Xbox360 instead of or as well as, because what they're giving out is mighty tempting. The PS3 has nothing for me...the controller looks like a boomerang with buttons, and I haven't seen anything on software, confirmed technical details, so I predict Sony to lose completely in this war.
Hope this helps with your feature, Lisa.