http://www.amazon.com/Microsoft-D67-.../dp/B00005853X
I use this one to game, and for everything. I had it since it came out, what, 9 years ago? It's far more accurate in ANY game, even an FPS one, if you just know how to use it and get used to it. The key is to use it for movement and aiming ONLY. The left button is move forwards, the right is move backwards. The center scroll, is also a button, and I use it for jumping, and if you scroll down, you switch weapons. I do not use the scroll up feature, because the scroll tends to move forwards while quickly jumping, and you don't want to accidentally switch weapons in a fast FPS firefight. The 2 side buttons are used for strafing.
I fire and do all other actions on the keyboard. Usually, I like to fire on the space bar, but some games I may alternate my keyboard setting if I need to use a variety of fire commands. Then I use F as a main fire key, and set other fire functions like reload or alt fire around that. If you instead try to bind fire keys to the thumb controlled trackball, it makes moving and firing extremely difficult and inaccurate. This is also true of the large middle ball trackballs, which for gaming to me are inferior to the thumb controlled one, because you have to use the fingers to control them properly, while managing out the other fingers for pressing buttons. Center controlled trackballs are just not as ergonomic for gaming setups, but are fine for other PC uses, like designing or surfing the web.
Another plus is, you can game or browse the web from the arm of a recliner or on your leg, with the keyboard in your lap, which puts your entire arm and hand in a more natural position for long hours of gaming or other PC work. Yes, it takes some getting used to, and you may hate it at first, but once you build up a little strength and accuracy in your thumb, you will wonder why you suffered with a mouse and moving it needlessly all over the desk for so long.
And I prefer the larger thumb controlled trackballs made by Microsoft, they fit my large hand better. I actually returned several different Logitech's and other brands before because they were smaller, for smaller hands, and they made my entire hand cramp up from the unnatural way I had to cup and rest my hand on them just to use it.
You could have argued that like 8 years ago. Optical/laser mice don't need to be cleaned.
Yea, this one I have DOES need to be cleaned on occasion. If any hair or lint blocks the laser, the ball has to be popped out and the lint has to be blown out of the gap. Also, lint does build up on the little silver BBs that hold the ball in place, and that has to be cleaned with a q-tip or clean cotton rag, or a shirt. And the ball needs to be polished a bit at times, too. So I remove it and roll it around in my cotton tee shirt a bit.
And this trackball has performed amazingly well after literally 10k hours or more of use, and all the buttons still work perfectly, in spite of dropping it on the hard floor at least 50 times, with the ball popping out and rolling away.