I put in 16gb and I've been just fine, but yeah, I don't use anything that's a memory hog other than the mtgo client, which is a flaming piece of memory leaking shit, so yeah actually maybe I do. I've been fine with my current build, though. I put it together for reliability and not e-peen 3d mark measurements, but if I'd wanted to spend 2k or more I could have really pimped that sucker out.
I think I'm gonna get a sager laptop this year for my Crimmus present to myself when I get a bonus, and I'll just alternate a desktop and laptop every year and keep writing shit off on my taxes until the IRS comes for me and I go out in a blaze of stupidity.