I think the mouse is the best gaming controller ever, it's easy to move, lets your hands not be clumped together like a system controller(besides wii that is) and it is very accurate if you're using an optical mouse(the balled ones are weird, they get messed up after a while.)

Anyway, the keyboard and mouse is the best way to play games I think.

Depends what for...

2D fighters - Saturn pad (I dare anyone to challeng me on this)
FPS Shooters - Wii mote
Sidescollers - Snes
3rd person Adverture/shooter games - 360 pad

Perhaps for FPS games, but not necessarily true for all genres. Take fighting games, it is much easier to control a fighter game with a control pad than a mouse. MMO games are much better on the PC with a mouse, but some games (FFXI) were designed for the PS2 and do not have great controls for a PC.

I only prefer it for RTSs, although I do have an awesome laser mouse

Well, some genres of games are not really suited for the PC such as madden, and adventure games like assassin's creed. The keyboard keys would have to be half their size so you wouldn't be reaching halfway across the keyboard to reach a letter.

And THE WII?????? How is that better than a gaming mouse for fps's??
It goes:
1. mouse & keyboard
2. Wiimote
3. Gamepad
The mouse it just natural, like in cod3 on the wii . although that may just be a bad example... (i did like that game though) you can't really explain it. well, I can't. more precision?

I use to prefer mouse and keyboard for RTS and FPS games, but after Metroid Prime 3 I think it's only best for RTS games.

Of course, it's best for all.

The Nintendo power pad was the most fun to use. The PS1 boomerang controller felt the best in my hands. The Wiimote with a condom + nunchuk is the best when it comes to control.

Mouse and keyboard are really good, though.  They are somewhat better than Wii for FPSs and much better than regular controllers. 

The mouse is no doubt that best hand tracking device plus the keyboard is best for most games except sports and flight sims. The wii- mote is more annoying since you got to aim at the  IR light bar from a distance. I like the wii mote motion sensor a lot more than it's IR tracking.

The mouse's main weakness is that it requires a desk...