Update: I had some time to fiddle with this build today, and there is good news and bad news. I installed the Antec 520W PSU today, and it seemed to fix the wattage problem, since I finally got some spin-up sounds from the HDD & DVD drive. However, still no video...at first. I looked over the manual for the umpteenth time, when I noticed the RAM was supposed to go all in the Channel A slots. Sure enough, I had placed them in the wrong slots. After a quick switcheroo, the system powered up and I had video! Huzzah!
Moral: RTFM: Read the frakkin' manual!
Unfortunately, what appeared on the monitor was a "Bad BIOS checksum" error. I went to my other PC, downloaded the newest BIOS from ASUS on a USB drive, and restarted the build. BIOS Recovery came up, flashed on the new BIOS, restarted, and...another "Bad BIOS checksum" error. However, I know the BIOS flashed correctly, since the boot loader went from v.022 to v.025. Thus, I must have a bad BIOS chip that has been the culprit all along.
Oh well, looks like I'm going to have to get an RMA from TigerDirect, unless anyone know a fix for a bad BIOS chip.