The current screensaver preferences thingy only lets you choose
the screensaver you want to use, after how many minutes it's activated, and whether to lock the screen when it is activated.

It needs a way to say when the screen will shut itself off for powersaving purposes, like xscreensaver-demo has.  

I don't think 4 different settings are necessary, however.  (I have no idea what dpms_off, _standby, and _suspend really mean, and I doubt many people do.  I just set them all to the same value.)  A slider that says after how many minutes the monitor is turned off (with 0 being never) should be fine.