Evilhugbear said:
My dad has bought from zipzoomfly.com and everything has worked fine.

is there a big difference from DDR2 800mhz and DDR3 1600? If there is I may get that processor and ram, but we will see.
DDR3 is coming of age, its what most new high-end PCs are equipped with today, DDR2 is still a good choice but its on the way out. For best chance of future upgradeablility, I'd go with DDR3 if I were building a new system for myself!