Just realised that PSNProfiles now offers a new stat: Average Rarity (of all one's trophies).
Currently mine is at 50.07%, which I believe is on the high end (whoring too many trophies that are easy/common). Most of you would be in the 40s, a select few in the 30s -- e.g. TBone = 38.55%.
My website: Precocious Ragamuffin