Land's End.
My daughter is using hers for the third year in a row now. Or is it 4 years? Anyway... their prices are a little more than you pay for something off the shelf at Target or Walmart, but the quality more than makes up for it. I spent about $25 for my daughter's... but that was 3 years ago and she is not easy on packs. She likes to THROW them into the car. :) If I'd bought a bag at Target or Walmart, I would have probably spent $12, and then another $12 halfway through the year when the lining starting ripping/tearing. Then another $24 the next year, and then some more this fall. But her Land's End one is still in great shape and DOES keep things cool.
I pop in a freezer wrap thing and lunchables, yogurt, pudding, chilled fruit, cheese.. whatever.. they all stay just fine. Her lunch is packed just before 7 am, and she eats around noon also. Hers has a separate compartment for the water bottle (which is also insulated), which is nice, b/c that way her PB & J sandwich doesn't get smushed by the weight of the bottle. Hers looks like one of the old timey adult kinds (where the lid is rounded and folds back), except it isn't metal.
Also.... freezing go-gurts and tossing them in is an idea someone shared with me. They're supposed to defrost just right by lunch time if you don't put in a chill pak or anything. I always do anyway (because I get paranoid), but I've been told you don't have to.
http://www.landsend.com/pp/MultiTaskLunchBox~197136_-1.ht...