In reply to suicidal optimist:
tough one, ideally i'd go with birkett - big walk in, big multipitch routes etc is what i love most about climbing. the fact that i'd probably have to prussik/jumar all the way up anything he wanted to climb however (i'd feel a tad silly battling my way up a vs with birkett watching)
and although i'm not really interested in bouldering - at least if i went with sharma i'd be able to climb other routes while he proceeds to climb super problems.
i'm reading into this far too much.
quite easily definitely birkett - even if he would no doubt make a complete and utter mockery of my climbing.