No offense but this types of threads are useless. You are the only person that can determine if it'll be worth it, and if you have to ask it probably won't.
Are you unhappy with the 6700's memory, size, external antenna, <add any other feature changed from the 6700 to the 6800>? If the answer is yes, are you willing to pay the price of the 6800? (Rumors say it'll be $550 without contract or upgrade rebate).
If you answered yes to both questions, then yes, it'll be worth it to you. My recommendation is to research the 6800, there's tons of info on these threads including a PDF file with all the specs, and then determine if you need it or cannot live without it.