Hope this might help, it might not be 100% correct but that's what I know:
1) It uses REGISTERED SDRAM, look for the "reg" in the memory description when purchasing.
2) From what I know it uses standard ATX 250W or better power supply so any current PSU should do the trick. Get a 300W just in case you plan to have a LOT of internal peripherals ( Hard drives, CDROMs, etc...)
3) If they are standard IDE drives the answer is YES. Otherwise, wait to see which SCSI card will be supported.
4) What's a flipper??

5) Wait for the compatability list, if it goes well, we should be able to buy any popular video card.
Hope this helps :-)