First of all, I AM WAITING FOR A NEW iMac AND LEOPARD TO COME OUT BEFORE I SWITCH!! I have a Dell Dimension 4700, 70gb HD, 512mb of RAM. 1. Will it be long for a new iMac and Leopard to come out? 2. While I wait, should I upgrade to Vista? I need to upgrade to at least 1gb RAM. 3. What would you do in my situation?