They are primarily a software company, there most successful and innovative items are mostly software related or tech that makes use of that software.
They aren't built on a bunch of innovative hardware really but the stability and integration of existing tech and software and improving that. This is something that the Xbox is for them.
Sony has so many failed innovative hardware products, UMD, the memory sticks, mini disc... just to name a few. But for some reason people love to list zune, phones, and mixer