After using shoulder bags and backpacks for years, I've recently started using a laptop bag with wheels.
I got a Travelpro one (I think it's the first one of these)
http://www.travelpro.com/rolling_com...utercases.html from Macy's where it was heavily discounted.

Lots of companys make similar bags though. The Swiss Army branded ones look particularly slick.

The wheels are such an advantage - my neck doesn't hurt after a trip any more, and now I don't care how long the walk to and from the gate is.