Best DB diagram/design tool?

A bit off the .NET topic but I've yet to find the *perfect* DB / ERD diagraming tool. What is your favorite tool?

wishes:

Cloud based with collaboration (sharing)

Embeddable

Can import/export SQL script

Can include all the table details (PK, FK, relationships, types, field comments would be cream on the top)

Import/export PlantUML support would be a nice bonus