For fly photos you're going to need something with good macro capabilities, as well as a pixel density of at least 2M. It should also be capapble of storing phtographs in an uncompressed format such at TIFF (which also means a decent amount of storage -- I found a 64MB smart card to hold about 15 TIFF images at 3MP.
I've tried several digicams over tha last few years: my wife's Olympus 340, the Canon S100, a Sony (I don't recall which model), and Nikon Coolpix 950 and 995. The only ones which met the above criteria for fly photos were the Nikons.
For outdoor work make sure whatever you have has an optical viewfinder as well as LCD, as the LCD will wash out in bright sunlight.