It's pretty early to know what kind of tools will be needed for Diablo 3. However it is pretty safe to say there will be some room for calculators of some sort, as well as some sort of web based character editor/planner

We'll have a better idea of what tools will be needed after the beta comes out, but in the meantime, feel free to post any ideas or suggestions you have for some tools. Also keep in mind, it doesn't have to be Diablo 3 related. If you have an idea for a clan tool, I'd like to hear them too!.

Thanks,
Redeemer