When my PC boots up it says "Press DEL for setup menu. Press F8 for Boot Menu" I just hit F8, and pick my Leopard drive. It works out well for me. My Win XP x64 drive is set as default for boot (for the old lady), and when I want to use it, Leopard is just an F8 away.

Setup

SATA hdd0 = Leopard GUID Drive w/ EFIv8
SATA hdd1 = Windows XP drive

Both have they're own bootloaders.