I would recommen starting by building yourself a nice working Gentoo system. You'll likely learn a lot. Once you've mastered that, try an LFS setup. Best way I know to learn Linux from the inside out is to build it yourself.
I'm currently (as I'm typing this) compiling another Gentoo as I am just not quite happy with the Debian I am using now. LFS will be my next project. I have a lot of time while I recouperating from a car wreck so am putting it to good use