I have almost the same setup except the Geforce card...
I'm running my pc on a M4-ATX and it was working just fine untill I decided to upgrade the firmware... (another story)
My setup is:
DFI MainBoard with 2,88 GHz Pentium 4 processor
100GB 7200rpm Seagate HD
Linksys PCI card
Few USB devices (like GPS, Bleutooth, Keyboard, Touchscreen, ect)
7" Lilliput Touchscreen (15 watts?)
So this is running on a M4, but I don't know if the M4 would be enough with a GeForce Video Card added...
In your setup the Video Card and the processor are the biggest consumers. Considering that a normal Pentium Processor "eats" in idle state already around 60 watts, and full running up to 110W!
I searched for the specs of your video card and I the specs that I could find were with a 350W recommendation...
I hope it would help you a bit with your decision, because that's up to you