Mac vs PC vs Linux as a development platform

I've been programming for nearly 15 years. I've been working with both PCs and MACs for about 10 years. Most of my programming exprience has been building web based applications that don't really realy on one platform or the other (from a client perspective at least as the server is usually linux). I feel that I am in a good position to judge what os/hardware set up makes the best workstation.

I've got an Ubuntu desktop, a XP Professional desktop and a new iMac running leopard at work. At home I run an XP professional workstation and G4 10.3 panther laptop. Depending on the workstation I run a variety of IDEs and programming tools including putty, Eclipse, WinScp, SlickEdit and a plain old terminal as the most prominent.

I think I've finally come to the conclusion that OSX Leopard is the definative way to go for the forseable future for one reason and one reason only.

It's quiet. I hate hearing a computer churn.