well fluxbox can be used with any distro really and i'm guessing you're not going to be very impressed with it after using win7/cinnamon/kde/gnome because its a bit(lot) lacking in features & sparkle, it is how ever very fast/stable/light and you could probably run it on a pentium 1
you should try out archlinux on your fannying-about-box if its at least i686, you can use Blackbox, Fluxbox, GNOME, IceWM, KDE, LXDE, Openbox, WMaker, Xfce, blah blah and it even has the packages for Cinnamon which i'm currently installing, the default install of arch is very bare bones especially if you're used to things like ubuntu/mint that come with everything preinstalled/configured. But it has an excellent package manager called pacman with which to build up your system.
the installer is text based & it's more of a ballache to get up and running than anything ubuntu based but it's worth it in the end because you end up with a bloat free & uber fast system