Nokia E61 (unlocked and unbranded) @ Next Mobile $598.90 delivered
The phones listed at $595 on the site but shipping is $12 so its not really 595. But once you calculate the phone + shipping - cashback - it comes out to $598.90 which is the best price I could find unless you arent paying by credit card. The cashback wont show on what you pay but will show in your earnings here.
Techoni was actaully cheaper by $2 on its delivered price but its got a 3% credit card surcharge and my assumption is that you'd most likely be paying on CC.
The price difference isnt huge, but I like merchants who wear the card charge.