I'm currently reviewing best/most efficient tools for a large UX production environment and would be interested in hearing experiences from other UXers who have been down this well worn path before.
The ideal solution for me would be one single tool that:
1. Generates greyscale wires (with a good widget library)
2. Outputs them in semi decent html for testing
3. Lets designers work out of the same file so they can switch out elements
4. Has a built in team review tool