I got 2 packs of 4GB (2x2) g.skill 1066. I like them a lot
EDIT: I suggest you look up specs on your mobo and see if anyone has had any issues filling all 4 DIMMs. Some people can't drop 8 gigs because their motherboard is finicky when it comes to using all available slots.
that's what i am planning on running as well, we have the g.skill 1066 1x2 right now and it works pretty good and it oc'd quite well