I am using Fedore Core 2 in runlevel 3 with fluxbox. When I boot up, I don't get a graphical login screen, and instead login and then enter the command "startx" to start fluxbox. When I close fluxbox I am dropped back down to the terminal prompt. There I enter the command "poweroff", which shuts down the system and cuts the power. I read the man page for poweroff, and I believe it said I needed to be root to issue it, but that does not seem to be the case....I can issue poweroff from a user login.
Hope this helps