Aluminum has better ram, and a slightly better screen than the old white ones ,more hard drive too I think..
no the aluminum has more expensive ram, that uses less power at higher frequencies.
benchmarks show that 1066mhz ddr3 will perform almost the same and some cases worse than 800mhz ddr2, these are both only drawing 1.8v of power.
whitebook has an updated nvidia motherboard, which is suppose to be a better mobile platform compared to the previous intel.
if money is a main concern just by the white macbook, if its not buy the aluminum unibody macbook. the main difference component-wise is aluminum has more luxury enhancements like LED backlit LCD, multi touchpad, newest type of memory (ddr3, which does not increase performance.) Besides that they will both have 2ghz c2d @ 1066fsb, 2gb of memory, 13in display, 4-5hr battery life (even though officially the white macbook is rated for 4.5hrs, while the aluminum is rated for 5hrs.)
minor details like 40gb extra storage space and, the aluminum macbook is ever so slightly thinner than the white macbook.