My old PC was fairly quiet but my wife always complains about the mouse clicks when playing games!

is there an optical mouse that has silent push buttons??

I covered some methods to make a mouse quiet here.

This is quiet, according to the website, but no one has used it and can say how good, quiet, or comfortable to use it is http://www.silentmouse.co.uk/

This might be quiet, but it doesn't say. It's expensive at $99, but it may be worth it if it annoys your spouse that much. I'd e-mail the company that sells it about the acoustics.

There's the Thanko Silent mouse, mentioned in the link above the quieting methods, but the review I linked to there showed it to be EXTREMELY uncomfortable to use to the pont where my hand was in pain after several days of using. Only for people with small hands. I would avoid, personally. Dynamism doesn't sell the keyboard any more. I have it, but the keyboard has such a high resistance that it makes your hand tired and sore after continuous use. Thanko has some nice ideas, but their execution falls short.