One very important difference I forgot...

If you like to configure everything from the CLI, Debian's core configuration files are much nicer than RHEL's. Compare, for example, "/etc/network/interfaces" as opposed to "/etc/sysconfig/network-scripts/*". This difference is enough for me to have X11 on my desktop just to be able to run "system-config-network" - In RHEL5, because on RHEL6 is either editing those awful config files or using the even more awful NetworkManager... bleh!