Greetings all, this is my first post, I hope you all can give me a little guidance. I have a dual G5 powermac with a 250gb hard drive that I would like to back up and increase its storage by getting a 500GB+ external hard drive. I just need to know if firewire is really necessary, or could I get by with just USB? I'd probably be doing scheduled backups (music, movies, photos) bi-weekly, but would also have the external running whenever the computer is on. Do I really need 7200RPM or could I get by with 5400RPM? Also does anybody know of any specific externals that have proven to be durable? The last thing I need is to lose everything. Thanks.