So here's what I'm getting from batteries (DIGRC-X).

energizer regular alkaline
135 pictures (+3 avis), 25% using flash, internal memory, 6 days

duracell regular alkaline
160 pictures, 27% using flash, external 256 MB CF memory, 6 days

duracell alkaline ultra m3 ($$$)
188 pictures, 46% using flash, external 256 MB CF card, 7.5 days

I just installed solar panel, I can't keep going out there every week to replace the batteries and reset the clock. We'll see how well the solar panel works.