While I'd like to standardize everything to AA, I find a few AAA items very useful and many items I carry are themselves smaller than a AA cell so complete standardization would be difficult.

That said, all my radios (receivers) are AA. One AM/FM/SW will recharge NiMH batteries when plugged into 110AC, can accept both AA and D cell batteries; I keep a set of AA's in that radio and would like to get four D cell NiMH batteries, so that if necessary I could pull teh AA batteries for other apps and keep the radio running on the D cells

Most of my lights are AA. The 4xAA UKeLED has great battery life and can run on alkaline, NiMH and Lithium AA batteries (although the hazardous area ratings go away if it's used with Lithiums cells). The lights that aren't AA are either 1xAAA LED lights I have for pocket carry, or 3D and 2D Maglites with LED bulbs that are rarely used. My CR123 lights have all been retired.

The lights and GPS attached to my bicycle are all AAA. So in a sense I've standardized to AAA for bicycle applications.

Back to AA -- my primary GPS and digital camera run on AA batteries. The GPS alone is a great reason to standardize on AA batteries. If you see me walking with a Garmin 60CSx, everything else I carry will also run on AA batteries, probably NiMH rechargeables with a solar recharger in my pack.