I have an older Microsoft IntelliMouse and I love it. I will never go back to a corded mouse again!
The only trouble I have with mine is when the batteries start getting low on juice. But that is fixed soon after it starts acting up. The mouse comes with software that will tell you when the juice is getting low before you start having problems, but I don't use it.

I think I change the batteries in mine maybe once a month.
I still use an old keyboard, have not made the jump to usb on that end yet (mainly because I'd rather keep as many usb ports open as possible). The cord on it does not bother me as I don't move it around much anyway.