Working system until you need to upgrade something. I feel like the BSD systems are really what you want if a system like Slackware is what interests you. They have a tightly integrated core system with the kernel, and a ports tree to compile software from source with automatic dependency compilation. A lot of ports can be found as pre-compiled binaries.
All this with simple old school unix tools such as tar, cvs and make. All config is text files, everything meticulously documented in man pages. Very easy to upgrade.