Google Now, or something like it. Forget about messing around with shortcut buttons and apps, I just want something that tells me what I need to know when I look at it. For example, as I get up to leave work I want to vibrate and notify me of traffic on my usual route. When I get to the airport I want my flight info displayed with the gate number.
Throw in some basic health monitoring (steps, maybe heart rate), a round face (square just looks stupid for some reason) and wireless charging. Most importantly it needs to be comfortable, and I'd expect it to be durable and waterproof so I can wash it off every now and then. Anti-bacterial coating would be nice too.
The Moto 360 is looking good on this front, except perhaps for the strap. It remains to be seen how well it works though.