Canon A95 Replacement
A610 and A620 are direct replacement for A95. Although I would definitively go with the A610 if I had to make a decision, I think that you can consider the A620 since it has 2 more megapixels which would mean a little more cropping for you and thus give you the ability to probably crop a picture in order to get similar zooming capability as 6x and get a 3mp(I think it would be exactly 3.1mp) picture or get a1.75mp picture with 8x zoom.
Then, if I may suggest, get 2 sets of good rechargeable NiMH batteries and don't use disposable batteries as much. With 1 set of 2300mAh Powerex batteries, I can take over 400 pictures, so if you take 300 in 1 afternoon, IMHO there is no doubt that 2 sets of NiMH batteries would last u at least an afternoon, you just have to make sure that ur second set has been charged recently(cuz of the self-discharge). That way, you would adopt both an environnementally friendly behavior and it would prove to be a friendly solution for your wallet. Finally you'd have to change the batteries much less.