I am currently using Logetic Cordless DesktopEx110, I bought it because it can be used for both left and right hand. But last weekend, I went to Harvy Norman and tested out a few new mice, seems that new mice with a more ball like shape(high in the rear or middle) feel much more comfortable as they have more support to you palm. which I suspect that as the EX110 have a relative flate shape doing poorly in that area-- when I need press a button or doing scrolling I have to bend my fingers instead in a more natural positions with a mouse which fits more to the hand.
I've read something good about ergonomic keyboard recently, and quite like the looks of the Logitech Cordless Wave and they bundle the LX8, the Microsfot 's E7000 might be too big a step forward and I've heard in some rare cases people never get used to it. All to all the Cordless seems a quite good deal if the LX8 is a good mouse and suit my need for a more ergonomic mouse. But hey, the MS Nature Desktop 7000 has a very comfortable looking mouse but I don't have a chance to try it out, if any one have some good experience with it please speak out, I might bought that one instead.
I used to use left hand for mouse as I have shoulder problem in the right after using mouse for a while, but I got pain in the joints in left hand fingers recently then switch back to right hand but seems the symptoms on the fingers come back on the right hand again and the shoulder have been better now and less a problem. So I don't have a problem with right hand only mice now but it will be a bonus if I can swap my hands for a mouse.
I don't have any experience about the ergonomic of mice except a browse in Harvey Norman last weekend so would like to hear opinions of others, and thanks a lots in advance.