I'm refurbishing an old PC to work as a home server for several stuff. I'm looking for a lightweight distribution to install in it, but with a decent package repository. A small image size will be appreciated, as I have slow bandwidth too.
Gentoo, at least, is an unspecialized metadistribution that can be used for whatever purpose you can come up with. It can certainly be put on a server, but for someone lacking Gentoo experience the learning curve might be a little steep, and depending on exactly what software you want, compiling it may take a while on an older machine.
So speaking as a Gentoo user, Debian is a not-unreasonable choice for this use case. It's certainly stable enough.