I prefer to just put my computer into sleep mode and also turn the monitor off when I leave to save electricity. Screensavers are pretty, but do waste quite a bit of electricity or battery power (by keeping the monitor on). I use no power management options because I almost always put my computer to sleep manually when I leave (except when streaming video). Even when streaming video, I still turn the monitor off for energy saving as well as privacy reasons.
To each his own. Do what you think is best for your system.