David Noble wrote:

I have debian running very quickly on a celeron 650/64 megs of ram. If you use a window manager like Fluxbox or FVWM, it makes all the difference.

Which is because the GUI is what tends to slow things down. For best security you should use a recent distro - any one will do - but for speed of operation on a resource limited platform you need to be very careful about the desktop/window manager and the GUI apps you use. Ian