What do you do? If you're just playing games and ripping DVDs, 12GB of ram is a waste of money. If you're doing bracketed HDR exposures in CS4 then it's worth the cost.

I don't see why you're leaning towards an X58 system either, the P55 platform is a better value. The only advantage X58 has is Gulftown support, unless you do professional level video work or HD encodes for a torrent group you're not going to use the 6-cores and 12-threads of a Gulftown enough to warrant the $999 price tag.