Sometimes the "chalky hand on hold" pic can look very good, but very often it's just hackneyed.
my personal fav. chalky hand shot - taken by me of course....
and my two fav bouldering pics, one of me, one taken by me (god I'm self-centred....)
I think the main criteria are a certain dynamicism (is that a word?) in the climbers movements so it doesn't look staged, a interesting setting (doesn't have to be pretty, just interesting), along with the usual photography stuff of being well composed, good light and colours etc.
of course, having a hot chick as the subject always helps too....