I cannot tell you how depressing it is to see little kids pulling wheelie suitcases around. Their bleak, road warrior future flashes in front of me, as I imagine them 25 years from now, schlepping through O'Hare on their way to yet another regional sales offsite in some generic suite hotel with an atrium.
During my years of near-nonstop travel, I never gave in and bought a wheelie, unlike many practically all my former colleagues, which isn't to say they're not nice folks, every one most of them.
But if you're not gonna go the all-checked luggage route, the Trunki is a fascinating option. You pull it through the airport and the kid rides on top of it. Or depending on how you look at it, it's a riding toy with suitcase-scale storage capacity that happens to fit in an overhead bin.
Brilliant concept if it works. The biggest issue I can see is keeping a rambunctious kid on the Trunki in the first place. Also, it's not clear how well the wheels do on tarmac, so if you fly private...but never mind. The 10m trip from the car to the plane's so short, it wouldn't make for an interesting ride anyway.
The Trunki is £24.99 online, for UK delivery only at the moment [trunki.co.uk via mathowie]
Also: modern-day-dad's take on Trunki from like three months ago. [moderndaydad.com]
I just bought my toddler a trunki suitcase. It's made the trips to the airport a little less boring for him and a little easier on his mom and I.