4x4GB of DDR2 is likely prohibitively expensive, especially for Intel systems as they couldn't use the "high density" memory. 4x2GB is much easier to come by. I have 4x2GB at home right now if you're interested. I took a picture. I have 4 sticks of that memory. If you're interested, PM me.
I built an Optiplex system a while back for a guy. I put my 4gb sticks in just to see if it would run, and it did. Forgot to pull them back out before I gave the guy his system back. Made me sick.. Still hoping for a set again someday.
2gb sticks would be ok.. Brand don't matter.