I'd wait for the iPhone 6 but I wouldn't wait in line at a store unless Apple has a online preorder and I am only in line to pick up a phone that I already paid for.
If you don't need a larger screen, there is nothing wrong with the 5s and it will easily be able to handle anything you throw at it for the foreseeable future. I mean the a7 chip hasn't even really been fully pushed yet, so it will continue humming along even if it's not "the newest" out
I did the preorder and have it shipped to my door! Shipping is free too! It maybe about 3 days later then picking it up at the store but it painless and no time consumed - waiting!