Is Obsolescence Good Computer Security?

caesar-auf-nihil asks: "I was recently considering a switch from dial-up to something faster (either cable or DSL) but my friend recommended against it since he said I was more secure staying with Dial-Up. His argument was that my connection's slowness and 'not always on' connection gave me better security since I was less of a target for many security threats. Now, I have never gotten infected, nor do I believe my machine is infested with spyware and/or controlling programs as it runs fine, but I wonder if the obsolescence argument is really good or not. Does Dial-Up really protect you or is this a false sense of security and I should just go ahead and pick a faster service and make sure my firewall is a good one and my virus definitions are always up to date?"