The PNY you linked to was 4GB and the Mushkin was 6GB, whats with that? Are you sure you require 8GB of RAM? 99% of people don't. If your not sure just get 4GB then upgrade if you need to.
I was planning on getting two packs of the 4GB PNY or that 6GB Mushkin on sale and then a separate 2GB Mushkin. I would expect that I'll require more than 4GB of RAM because I'll probably want to run Windows 7 with a Linux server in a VM. I imagine it's going to get tight with only 4 GB but let me know what you all think.
I didn't double up on the 4GB packs of Mushkin because the rebate will only work once I figured it might be cheaper to grab the 6GB pack while it's on sale and then a random 2GB Silverline later (as opposed to hoping for the 4GB pack to go on sale again). I could just get the 4GB for now though. DDR3 prices have been going down. Buy now or wait? Corsair XMS3 is $60/2x2GB at Fry's as well. http://www.frys.com/product/6009088 although NewEgg had a lot of DOA for that product so I might trust the Mushkin RAM more.