MS will try to create the "Service" which will be an gaming service for multiple devices, mainly for windows 8. They will offer in this service what xbox live is but with cloud gaming and many other digital distribution systems and will initially hit an hurdle because being ms they will charge an monthly fee ontop like for xbox live and consumers wont get suckered in when they have services like steam offering for free. But MS will go for the service and they wont have an console but unlike steam (but who knows what valve has up there sleeves) MS will have it running on many different products from tablets to tv's without the box.
SONY wont go boxless but will again combine boxes into one box, so the first thing will to combine digital recording devices in (eg. combining play tv into the box) and offer an gaming machine, blu ray player, ditigal recorder, music playback, radio, tv. Basically the one box for them all. They will expand there online services to give major competitive edge over Nintendo what appears to be backwards/slow approach to online and remain disk based with digital distribution (steam integration?) giving them an edge over MS by remaining disk based. While SONY will push power they will not make the mistake twice and will try to make an cheap and easy to develop for console to become the "3rd Party Home" when it comes to developing games for, which those titles have been held by ps1 and ps2 is the reason why they are mega successful.
So to sum it up, MS will introduce an service and get away with disks and the box, and will most likely have the best cloud gaming system. SONY will continue its tradition of combing tv boxes into one super box but will focus on easy to develop for techniques. An Nintendo will fail because they will have not done enough to compete with what sony will develop for and on an price point, like what sony did with the psv will have an set price of most likely 399.
Of Course That's Just My Opinion, I Could Be Wrong
