I spoke with the Asus tech support and have it all figured out. You are correct, the PWR fan header is strictly for the power supply fan. My PSU, a OCZ Stealth X Stream 700W, doesn't have a dedicated connector for the fan, so the header on the Motherboard I've left unconnected. For the CHA fan header, he recommended I connect the rear fan, which I did.
As for my NZXT Tempest (case) and its six stock fans, well the reviews on this baby speak for themselves (check out Newegg). Its not unlike other midrange gaming cases with 4-6 fans. They all work great and are extremely quiet. In fact, I'm blown away by this case and would recommend it to anyone wanting to build a rig. This is my first and it all went together almost too easy!
My baby:
3.1 ghz AMD Athlon 64 X2 6000
Asus M3A78-EM Motherboard
G.Skill Pi 2X2 GB 4-4-4-12 RAM
Visiontek Radeon 4850 HD video card
Western Digital Caviar Black 640 GB hard drive
Asus 22X Optical drive-burner w/ lightscribe
OCZ StealthXStream 700W power supply
NZXT Tempest gamer case
when the tax return comes in: Acer 22" WG LCD Monitor
All for about $700, can't beat it!