The 360 in NA had good marketing to the right demographic, and they played well the card of the online community which is an important asset to that demographic: I don't want to over-generalize and sound trenchant about frat-boys, but in most of Europe there's no such thing as the dorm community of American colleges.
Nor there seems to be the same extreme reaction to the marketing: in Italy I don't think there have ever been things such as midnight launches, nor collective craze about a console or a game justifying queues of hundreds of people outside retailers.
Plus there's always been a strong PC gaming presence and a vivacious hacker scene, which reflects into
a) a tarnished image for the MS brand
b) the perception of the 360 as a second-class PC because of the gaming genres, availability of exclusives etc. The PS3 probably looks like a better complement to a "real" PC.
Essay Pro