We bought one from Pottery Barn Kids last year along with a matching thermos and lunch bag. Not cheap by any stretch. I think for all three I paid close to a hundred dollars.
The thermos heats wonderfully and stays hot. The lunch bag is roomy and well made. The backpack fits all of his things perfectly, has tons of useful pockets and straps, and fits everything he needs to bring. Also padded in the right places to be comfortable to wear.
We bought a design he could use for a few years so that it wouldn't look too babyish as he got older.
After a year of use it all looks BRAND NEW. I could not be happier with the quality of these items!
ETA) My son is hard on backpacks. I finally went with this one because he was going through two every year between rips and zippers breaking.