I'm kind of on the fence. There are times when I want to really sink into the game, totally immerse myself. That's when I pop on the surround-sound headphones, break out the joystick (FFB2, BEAST of a joystick), and ask my wife if there's anything she plans on telling me in the next 3 hours (she understands: she's a gamer too). Sometimes I just want to kick some Shivans for half an hour, and that's when I play with the mouse.
For mouse players, some suggestions:
Get a hi-res, hi-sensitivity mouse. 1000 DPI is bare minimum. I highly recommend the Razer mice. I've been using them since the ball and 2 wheel days, and they're fantastic. There are a lot of gaming mice on the market now, though, so you've got options. You're looking for something between 1k-2.5k DPI (yes, you can still find dense core 2.5k DPI ball mice if you do some hunting, and they are still more accurate than most optical mice).
Learn to play with your fingertips. With resolution and sensitivity cranked, you should be able to rest the heel of your hand on the desk, your fingers resting on the mouse, and move the mouse purely with the motion of your fingers. You should be able to do a full 360 without lifting your hand. This style of control takes a LOT of practice to get used to, but once you do, you'll never go back to full-arm mousing again.
Individual preferences vary, but I find I need a *heavy* mouse. Many gaming mice have adjustable weight systems. This feature will cost ya plenty extra and the weight is almost always on the back end (not evenly distributed across the mouse) which can lead to accuracy issues. If you're the DIY type (which I am), there's a cheaper and better solution.
First, get a tester mouse, of the same tracking mechanism (ball or optical) as your preferred gaming mouse. The magic word here is CHEAP: you can get a mouse of either type for $5 or less, and that's what you're looking for. This is your "practice" mouse, the one you're going to modify first to make sure you've got the process down before touching your $50-120 dream clicker.
If your mouse of choice is a little on the flimsy side, open it up. You'll find that there's a LOT of empty space inside it. Once you've undone the screws, you'll find that the shell of the mouse is in two pieces: generally a top, rounded shell with the buttons and wheel and a bottom plate with the electronics. Don't worry: we're not messing with the buttons or circuit board.
Most hardware stores sell metal joint compound. The package should have two tubes with one nozzle and a plunger on the back. This stuff is HEAVY, nonmagnetic and nonconductive, and thick enough when you initially apply it that it stays where you put it.
Take a look inside the top half of your disassembled mouse. There should be some areas clear of all moving parts and electronics(at least 5mm). Put the two halves of the shell back together to make sure you've got a good idea of the areas that remain clear when the mouse is reassembled. There should be quite a lot of it: most modern mice are mostly empty space. We're going to fill a little bit of that space up.
When you've got a good idea of your safe surfaces on the inside of the mouse, it's time to grab your tools. You will need:
heavy and medium-grade sandpaper
a glass basin of hot water
a sponge
a cheap plastic fine-tooth comb (rat-tail works best)
the metal joint compound
Start by abrading the clear surfaces with the medium grade sandpaper, THEN a quick scuff with the heavy. This creates a good, uneven surface for your compound to grab. Apply a small blob of the compound (about the size of a pea) in the center of each area and spread it with the comb. You may need to bend the comb to get the angle right. After the compound is spread, rake it once in each direction (vertial, horizontal) with the comb. This will provide a good working surface if you find you need to repeat the process to add more weight. This is a process of fine adjustment, and little differences can have a drastic effect on how the mouse feels.
Use the tail on the comb to clean out excess compound in the mixing tube (the little part at the end where the two tubes meet). Clean the comb with the sponge and hot water.
Allow the compound to set. Depending on the brand and type this may be anywhere from a few minutes to a few hours. Reassemble the mouse and give it a test drive. You may find that it's not yet heavy enough: repeat this process as necessary.
Experiment. You may find you like your mouse with the weight centered at the rear, distributed along the sides, etc. I prefer mine weighted a little to the left to off-set the natural bend of the wrist, but that's just me.
Once you've got a good idea of exactly how heavy you like your mouse, you're ready to try it out on the real thing.
Congratulations. You just learned how to make a professional quality gaming mouse out of something you picked up from Best Buy.