personally i think white phones just look huge. maybe because of the stark contrast of the black screen (when off) and the bezel, but it looks way bigger than it is. White may sell better, but i do agree it gets dirty really easily. This is easily compensated for with a black case or something.
about the colour of the bezel, ie. comparing the one x and then gnex side by side, its about the same, but the one x looks HUGE cause of the white bezel, while my gnex looks smaller and just like one slate altogether cause its black. i've played with the pebble blue one which is SLIGHTLY bigger than the gnex, but i've also heard that there is other colours coming out soon, so if you're down to wait and see...
so if it were me, i'd get the pebble blue. but then again if it were me, i would also not get something other than a nexus.
but thats just my 2 cents.