I typically fill up at 2 pips. I don't wait for low fuel warnings. At 2 pips, with a little massaging of the pump handle I typicaly get about 7 or 8 gallons in each time. So long as the gauge fills up to F, I'm happy.

It has been said:
Hybrid drivers come in 3 flavors, greenie, techie and cheapie. Pick any 2.
2005 Prius, Melinium Silver over gray, package 5 (AI)