DS1 just went gluten free in June and even though I eat pretty paleo and avoid GF grains because even they make my stomach burn, DS1 is 12 and just wants to eat normal food like his friends sometimes. So we have been experimenting with GF replacement foods for him. Mostly breakfast foods since my dinners are usually paleo or at least low carb/grain free and DS's school has a great lunch program with about 12 meal choices a day, usually 2 or 3 that are gluten free so he's able to buy lunch most days. He's is currently nut-free and coconut-free as well, so although I'd much prefer to use almond or coconut flour to make an equivalent food, that is not possible.
Some of his favorites (given the thumbs up by 6 year old DS2 as well):
GF bisquick to make pancakes (this is surprisingly good and DS1 says they're just like regular pancakes. I add fresh blueberries and banana slices)
http://www.amazon.com/Bisquick-Panca.../dp/B004391DK0
Trader Joe's brand GF bread. I use the "white" one for making French toast and the "whole grain" one for toast and tuna or egg salad sandwiches.
http://designassets.traderjoes.com/U...ee-breads2.png
Betty Crocker's brownie mix (these taste just like regular brownies. I add an additional 1/2 cup of TJ's chocolate chips and cook them a little longer. Made brownie sundaes for DS1's 12th birthday 3 weeks ago and everyone loved them).
http://www.amazon.com/Betty-Crocker-.../dp/B002AQP5MK
Crunchmaster multi-grain crackers. The veggie ones are perfect for eating on their own. The sea salt ones are more plain and good for dipping, eating with tuna, etc.
http://www.amazon.com/Crunchmaster-M.../dp/B0060L6I9U
http://www.amazon.com/Crunchmaster-C.../dp/B004H1YIBU
TJ's GF plain bagels (DS1 says these taste like regular bagels)
http://designassets.traderjoes.com/U...ain-bagels.png
Udi's GF cinnamon raisen bagels (DS was in heaven when I found these at Ralphs!)
http://udisglutenfree.com/wp-content...ducts/1693.jpg
For cereal my kids love this one and it actually has some fiber unlike most GF products! Not in stock on Amazon right now, but is usually $3.xx a box
http://www.amazon.com/Vans-Natural-F.../dp/B00CTDVJDI
GF rolled oats (I sometimes make overnight oats with fruit or I grind these up and use them in my meatloaf muffins, salmon cakes, etc)
http://www.amazon.com/Harvest-Gluten.../dp/B004KUV136
GF instant oatmeal packets (this brand seems to be the lowest in sugar)
http://www.amazon.com/Glutenfreedas-.../dp/B002AUF15C
For snacks he'll have naturally GF foods like string cheese, salami, yogurt, pickles, and meat sticks. He was dairy-free for years, but we were able to bring it back before going GF so that has definitely made it easier.