I can't say for monks, but for bruisers the pwr pool is derived from strength (according to some posts from everquest2.com forums). I haven't really tested it myself.
A question I have is where do HP come from on a bruiser? I always assumed it came from Stamina, but now I'm not so sure.
Yesterday I (lvl 21 ratonga bruiser) was grped with a lvl 20 ogre bruiser. My stamina is 32 and his was 33... but I had 818 hp and he had 550! The +health I got from items added up to +86 and his was around +57. The only major difference in our stats was that my agility was 79 and his was 49.
Could it be that agility determines HP in bruisers? Most curious....