Check out Repco. I bought a top box and trolley from there when I started my apprenticeship, and it's still going well. Brand is Senator. I've got a Sidchrome top box and trolley at home too, which I reckon is even better. Really nice boxes. They were both $1000 wit a bunch of tools, picked myself up a bargain.
Stay away from Snap On! It's fucking awesome, yes, but no way worth the money! You can get just as good for a lot less of the price. And when you dent it, get some dirt on it or it gets stolen you won't be screaming! I'd think about getting Snap On only if I won the $30mil powerball, but then I wouldn't be working!
I had an old Kinchrome trolley for a while too. Wasn't anything great, but it was cheap. Drawer runners wore out pretty quick.