if i edit my mf files in he laptop on location i am always a bit suffering from processing power on location, so i tried to "tune up" my macbookpro 2x2,2ghz and not to upgrade to the new mbp cause the increment of the newer mbp doesnt seems to be worth the upgrade, more so because i hate these reflecting screens.
i upgraded now my internal ram from 4gb to 6gb, which is the ( inofficial ) maximum, i built in a fast 7200/ 500gb drive and - by far most important - i bought a 50Gb SSD flash card memory to put all editing programs and temporary files ( photoshop, lightroom, bridge ) on this. reading speed of the ssd drive is app.10 higher than harddisc, writing speed app. 3 times faster.
the result is incredible. i havent measured it, but subjective photoshop works at least twice as fast than with the normal 4gb internal ram and 5000/320gb hd, the programs ( which are on the flash drive ) open in few seconds ( incl lightroom with large image banks ) and no more problem to let run and work several of this programs together.
these are highly highly recomendated tuning steps, the result is surprising.