I'll be using a mini-itx intel 478 atx mobo

proc = 25w
mobo = 20w
pci sound car
pci tv tuner
1 x 40gb ide hd
1 x dvdrom ide drive
256mb mem
4 or 5 usb devices

i get about 75-80w total

think i can get by w/ m1-atx?
usually the calculators add power usage based on 80/90% power comsumption. so i am hoping that it might be 60w with the small usage i plan on.

how efficient are the m1-atx's?