The official line I think is that it has to be state-recognised ID (e.g. Florida driving license, military ID etc). In most places any photo-ID will PROBABLY be OK but at the end of the day it's up to the establishment in question.
I remember having a particularly colourful exchange with a supermarket checkout girl in Poway because she wouldn't accept my UK passport as ID. I guess my "If it's good enough for YOUR US Customs Service it should be good enough for this ****hole" could have been phrased a little more diplomatically, as could my "Can you READ that? It says 'Without let or hindrance'!". Needless to say I got a smile that said '**** you', a "Have a Nice Day" and no beer. Serves me right.
The only sensible advice I can offer you is if you plan on using your UK Photo Driving Licence or UK passport as ID make sure the photo is a RECENT one. Have a nice trip.