Will my PC upgrade parts be compatible with each other?

The motherboard and proc are both LGA 755's so they will work fine. You didn't list what RAM you have, so I can't give recommendations there. The board supports 4xSata2's so you're good on the hard drives. The mobo supports 4xATA devices so that works for the DVD-R's as well. There are 2 PCI-E slots on the mobo, so that will work fine with your video cards. I couldn't find any info on your heatsink/fan unit but since most procs are the same approximate size, it should be fine. And that power supply - you could power quite a best with that thing. The 350 might have been pushing it, but the 700W...you're good to go. As far as I can tell, it seems like they will work fine. In fact, I'm a little jealous. :P