Re: Built my first migratory pallet today.
I like a treated plywood. I would also suggest drain holes in each back corner. Nice advice from Phil, don't underestimate the weight that will be sitting on them. The first prototype is a good time to decide just the way you want them and then stick to those exact dimensions. Its the vital element in having uniformity in your loads, not just so it looks nice but so they can be easily secured. 1/4" or 1/2" difference may not seem like much until you stack them up as much as 7 high on a truck and suddenly you have a jumbled up mess with gaps under your straps allowing lids to slide out.
"People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney