Constructed all from 3/4" plywood.
Since Autumn wanted to paint the cabinets, I fabricated the beaded faceframe out of poplar.
On a side note, Norm points out in his first episode that you should buy the best products you can afford, because of the investment you're making into your kitchen.
Because I'm just your average working guy, and I wasn't sure how far I would get before I screwed everything up and quit, I constructed my first cabinet carcass out of sanded 3/4 plywood (cheap), and NOT cabinet grade wood (not cheap).
My original thought was in this drawer cabinet section, you'd never see the inside anyway.
The time I spent dealing with warped & bowed plywood, I should have followed his advice and invested in better, more stable, plywood.