thinking about selling my late 2008 17" mbp for the rmbp but i'm not quite sure how much it's worth. it's got 2.5ghz core 2 duo, 6gb ram, 320gb 7200 drive (or i can leave my 256 crucial m4 in it and charge extra), glossy 1920x1200 lcd, upgraded to Lion. the machine is very clean, used a keyboard cover for nearly all of the past 4 years. can anyone help give an estimate on how much I can sell this for? thanks.