Xbox One for social features and I like the "Xbox feel". It was the last console I bought, actually.
WiiU because if brand loyalty. It was the first one I bought.
PlayStation 4 because of variety and power and (at the time) the promise of what was to come.
Last gen:
Xbox 360 because I couldn't find a PS3
Wii because Nintendo (it was hard to find. Took MONTHS!)
PS3 because I needed MGS4.