What Campaign Management tool do you use?

It is very common situation when you are running more than one campaign at a time, where few are in planning, few are under requirements or waiting for assets, or segement or some external process. What's the best method or tool or process you have in place that helps you track on weekly,daily or on-going basis?

Any feedback on how it is working out for you would be helpful.

Thanks

Amit Pandya