Countertop material recommendations
 

I am going to have new cabinets installed and I am going to do the countertops myself. I will be tiling it. What is a good material to use a top on the cabinets to lay the tile on? Should I use a thick layer of particle board then a layer of cement backerboard?

I personally like a good multi-ply plywood for stability under the cement backerboard.

Great choice but I would prime the plywood and also run a bead of silicone around the edges before you lay the concrete board down on the plwood just so if any water sneaks by it won't find its way onto the plywood and wipe off any excess silicone off the edges of the plywood.

If you want a basic by-the-book recommendation you would use two layers of 3/4" exterior grade plywood, then a waterproof membrane, then cement board and I would install the cement board into fresh thinset.:)