That's a tough question, one I'm not sure I can answer.
On the one hand, the Wii went viral with the casual market, which was obviously a big deal, but I don't know how much it shaped gaming outside of it's own sphere of influence. It expanded the market greatly but it didn't change the existing market all that much. Sony tried to squeeze into that market but I think it was already starting to wither by that point.
Sony's Worldwide Studios is big for me, and a major reason why I bought a PS3. They produce such a wide variety of high quality games with arguably some of the world's best studios. Games are, after all is said and done, what this hobby is about. They also introduced PS+, which I think could have a big effect next gen, though it was introduced too late this gen to make a difference.
However, I think I'm going to go with the 360, even though it's not my personal favorite. It launched first, and in doing so, I think it set the bar in a few areas, such as online gaming and multimedia support. I don't know that Sony wouldn't have done the same things regardless, as they also had the goal of turning their console into an entertainment center, but Microsoft got there first. In my opinion, the importance of seamless online connectivity outweighs that of motion controls. Of course, Microsoft also brought forth its own motion control scheme, but I think that is something that's going to be a bigger deal next gen.
