graphics - 8800GT has no competition atm - first choice!
cpu - q6600 is still sweet and goes to at least 3GHz oc'ed. You wont see much advantage in lfs of the four cores, though.
motherboard - anything that allows you a very high fsb, in order to take you c2-something to the max.
power supply - you current should do just fine, power-wise
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I have a c2d e6320 oc'ed to 3,5GHz, 8800gts, three harddrives and two optical. My generic cheap 420w supply does just fine and I have measured actual usage to max. 297w doing 3dmark, encoding movie and encoding rar file at the same time. 8800gt will use less power.