I had a Sony Clié at one point, but found that my cellphone's calendar and addressbook were about as useful - so I stopped using a PDA all together starting about two years ago. Really the only advantage the Clié had was it was easier to set up new calendar entries on - but it's pretty rare that I have to make entries when I'm not at my computer, so that's not a particularly compelling case for hauling a second gadget around.