If you need to permanently change your IP address, cable isn't the best. Sometimes you have to leave your modem off for 7 days to get a new one. Most DSL changes everytime you power down the modem. With dial-up you share an IP address with the millions of other customers that use that provider, making you annonymous/unbanable.

If you are concerned about you IP on the web, check out www.proxify.com, it's free, except sometimes during peak hours they will only offer it to paid customers.