Zim,
I have had 3 olympus’ in the last 3 years. 1st one 2 megapix, 2nd 2 mega pix with a 10x zoom, and my current one is the 3 megapix with an 8x zoom. The move from 2 mp to 3 mp I thought was an improvement. The ? I have for you is what will you use it the most for? I like the added zoom for taking several outdoor shots, but this bigger lens makes the overall camera bulkier and heavier. If you are only going to use it for fish pics I would go for the 2mp version for its compactness and ease of use. As a side note, if you plan on doing an number of 8×10 pics the 3mp is the one to get, the 2mp is good for up to 5×7 max for good quality.
Models C-720 8x zoom , 3megapixels
C-700 10x zoom, 2 megapixels
510??? 2 megapixel(? zoom )
Any further ?’s feel free to drop me a PM!
~~~~~~~~~alkfish