However I've been through everything and still nothing.
I should point out that this isn't the first time the mobo, ram, and cpu have been together, so I'm fairly sure its not something related to them or the BIOS.
Further, my issue isn't that the system won't post/boot, but rather that power doesn't seem to be getting past the mobo (recall that the mobo light is on when its plugged in, but when I hit the power switch nothing happens (fans do not turn on even).
You can bridge the two power button pins on the motherboard to bypass the case switch. I just use a flathead screwdriver. If it starts, the case switch is bad. If it doesn't start there's something wrong with the motherboard or the ground. Have you double-checked the motherboard stanfoffs?