I reworked the Wiki page to cover a lot things from this thread and IRC. Thanks for the discussion, The diagram was certainly misleading without explanation.
http://code.google.com/p/gosu/wiki/WindowMainLoopThe remaining question is this. Where in this loop does the sleeping/idle time occur? Seriously, I don't have any clue since it happens thanks to screen vsync nowadays. Even when glFinish returns, I don't know if this means that the data has been transferred to the OS, to VRAM or to the screen. Maytsh, I think your ideal order depends on this fact and I hope nobody is ever fast enough of a gamer to notice it. ;)