I’ve always been a fan of Linux From Scratch (LFS). LFS is basically an in-depth guide to building up a linux machine from NOTHING. Literally. You compile everything from source, including the kernel. Very very cool. I’ve done at least three LFS builds and one of the things that was challenging was knowing where to go when you were done.
Beyond Linux From Scratch (BLFS) fulfills that need. This guide starts off right where LFS ends and walks you thru the rest of a complete Linux system. Lately I’ve used Debian more than LFS because I can get up and running so much faster, but I might have to go back to one of my old LFS systems and take it thru BLFS.