Another +1 for Linux From Scratch.
"Now, I don't want to get off on a rant here, but..."
I was involved with those guys ten years ago; still have one of the very first print copies of the LFS 4 book. Big thanks to Jesse Tie Ten Quee (highos) and Gerard Beekmans for all of the tough work in the early days!
Seriously. Spend three months working with Linux From Scratch, and you will have a depth of understanding that will carry you through many years of linux. I moved on to Gentoo (just -Os -pipe, thank you, no rice here.) and then onto Debian and Ubuntu, where I've stayed for quite a long time.
I dislike the redhat package management and mirror setup, and I find "add-apt-repository ppa:freenx-team" to be quite friendly and easy to deal with.
I simply don't have the time to tinker that I did in my youth, I don't have the energy to './configure; make; make install' for every package, and things like Zentyal and ROS sitting on top of Ubuntu gives a nice range of application specific derivatives without spending a lot of effort to set them up properly.
"...of course, that's just my opinion. I could be wrong." -- Dennis Miller