Absolutely nothing. There is nothing either console has shown me that's given me that 'I need this in my life' moment. The only things I'm sad I'll miss out on are KHIII and Sunset Overdrive (disappointed to see Insomniac turning their back on Sony after all these years, anyway) but, given that HD remakes are becoming more and more prevalent, I know that one day I'm going to get to play them on something.
On the other hand, I am now planning to pick up a WiiU, despite the fact I've spent the last ten years shitting all over Nintendo. Maybe it's the fact that they're constantly coming out with either new IP's (Wonderful 101) or obscure sequels no Triple-AAA console would touch (Fatal Frame) or the kind of franchise-wanking I can actually get behind (Hyrule Warriors), or maybe it's just because their games actually look different and fun and colourful and not just a legion of sequels to the same old boring beige corridor-trudging shitefests I played all of last-gen.
That, and I think the gamepad actually has true potential for some innovative practical applications to gaming, as opposed to the bells and whistles horseshit the Wiimote gave us.