Microsoft D67-00001 Wireless Optical Trackball Mouse - Ergonomic Design for Office Work, CAD Design & Gaming | Comfortable for Long Computer Use

While I don't always think M$ is a computing Godsend when it comes to software, this trackball is the best input peripheral I've used yet.I have what I think is a larger than normal hand, so I find most mice and trackballs are too small for me to use comfortably. This causes my hand to tire out rather quick. This trackball however is of a decent enough size for me to rest my hand on without much fatigue.The USB PS/2 adapter is a nice touch. I love the narrow back/forward (By default) buttons on the outer edges of the primary and secondary buttons. Web and folder browsing is definately faster with those. The scroll wheel button as a double-click also is a nice option.For those hardcore mousers out there, it will take a bit of time to get used to a thumb ball, but I think it pays off as I now feel that I have better control. It also requires less desk space because the unit doesn't have to move around a la mouse. Mouse pads need not apply as well. Some grit occasionally gets in the small bearing that the ball moves on, but they are easliy cleaned with a brush of the finger, and they never get as nasty as regular mice.The software is nice and easy to set up with a graphic interface that shows the buttons you are setting. I know some people that can appreciate that.I bought one a while back for home, and then asked work to '[give]it up' and help out my ergonomics. Now my other home PC is needing one.My one gripe with this trackball is that it could have been improved upon by layering it with a thin coat of rubber to make it even more comfortable. This is a small gripe to be sure, as I can be at the computer much longer with this than a conventional mouse before my hand bothers me.