[Update]
Installed Ubuntu 10.04 LTS 64bit which went clean as clean could go. I started with 4Gb of ram and then once it asked to be rebooted, I added the other 4. Boot up screen said something about being unable to boot (kill engaged or something) and just stayed there. Powered down and took out the one I was the offender (the one I've always assumed was screwy). Tried to boot, made it to the login screen but when I entered the password it brought me to the pretty purple splashy screen and stayed there. Manual shut down and then removed the other offending chip.

Back to square 1 I guess, I'm going to bring back both of the ram chips tomorrow because clearly they aren't working even in the 64 bit OS.

*smacks head on keyboard in frustration*