Yeh and also, you are better off getting 6GBs of RAM instead of 12, because getting 12 requires getting 2 seperate kits, and means having 6 ram modules. The end result will be a lessened overclocking potential. 6GBs is much more likely to overclock better. Then again if you get ridiculously fast ram that may not be an issue...
Having said that the difference in peformance between the best build for $3000 and one for $7000 is probably at most 10%... imo not worth it.