For the past decade I have been using (faux) leather bound, grid ruled scientific notebooks, first from BookFactory (http://www.bookfactory.com/) and then from Scientific Notebook Company (http://snco.com/).

These lab books are designed to document work for patent purposes, but I find that they are great for all manner of design and implementation writing.

Unlike the cheap shit you find almost anywhere else, the bindings are incredibly durable, and you can lay them flat, like a spiral notebook. You can paste printouts directly into some of the larger versions. The quality of the paper is very high. For a small fee, you can have your name embossed on the cover in gold leaf.