Hi all, I'm relatively new to macs so have a couple of questions. I've just bought an iMac and got all my stuff transferred across. The guy i bought it off tried to sell me his time capsule(?) which I couldn't really afford. Do i need this or can I just simply back up to an external drive (i.e. I have an old seagate one which I guess I can just plug in?) Does the time capsule bring anything new- see they're pretty expensive on the apple store!!