I use a Logitech Trackball Pro - with the right thumb ball. Fits my hand naturally and is pretty darned comfortable - I still get days where, due to how long I use computers daily between work and gaming, I get some control issues - but it is much better than a standard mouse for me.

well m8 , i use the mx518 which fully supports the hand.
i hardly get tired of clicking thanks to this.
it's also a mouse that clicks very easy so you really don't have to press hard to click.
if your having problems after gaming 1hour you should think about getting a softer mouse :)

Cypher seems on point here. The weight of my hand holds down my mouse buttons for me. Kind of like they say you're supposed to play a piano by just letting your fingers drop naturally instead of jabbing at the keys, holding the mouse down is actually the relaxing part for me. Perhaps you need a different mouse.
FWIW, I find that using a mouse too small for my hand results in a lot more strain, and moving at unnatural angles. Lots of mice are pretty dinky. You might want to try some bigger mice, if you have moderate sized or larger male hands. A lot of Logitech's higher end mice are hand-fillers. Some even have thumb rests, which can be handy.

fully agreed mate. come to think of it , do you use a laptop mouse?
yes?
get rid of it ASAP for gaming purposes.
this is my current rodent [url]http://myego.cz/img/razer-logitech/mx518.jpg[/url]
as blarg says it has a thumb support

dont be ridiculous :)
There is no need for "special" mouses cats keyboards.All those items are only for profit.
Gaming is like playing guitar.If you never took guitar in your hands you will whine after 5mins how uncomfortable, not agronomic guitars are...
so.everything is ok as it is, dont waste money on lame items :)

You obviously have never suffered a repetative strain injury from using a mouse all day for both work and then to game. Use a computer for 10 hours or more a day for a couple of years and then come back and say that...
I found that using a mousemat with a gel pad sorted most of my problems, just being able to rest your wrist on something soft and in a more comfortable postion did wonders for me. Then just find a comfortable mouse that fits your hand.

Indeed , i'm a designer and a hardcore gamer. If you suffer from an RSI it hurts like hell and you are way to embarressed to stay home because of it.
I bought 2 logitec MX518 in the beginning of the year.
1 for work and one for gaming. The high DPI limits the movements i have to make + my hand is fully supported. Up untill now i didn't suffer from a second one.