Hey jt1,

interesting, you'll be the 1st to test 4GB 800Mhz dimms on the mobo
You can use the HR-01 X heatsinks, but only with an appropriate case. You need one that features the correct standoffs so you can screw the Thermalrights directly to the mobo tray.
The HR-05 IFX is fine for the NB, attaching a fan will be tough though. You definitely need a slim fan if you populate the 1st ramslot (which you do with 4 sticks), something like 70x10mm or 80x15mm (don't know if the latter existis, but there are slim 70mm fans).

About the PSU, depending on your GFX card I'd rather go with the 620 HX. Linpack drains more power than anything else on this planet, so you'd better be on the safe side.