Work Sets for Mac

From Tinnef Software:

Work Sets is an innovative application that allows you to capture and restore the state of your Macintosh. Work Sets will remember which applications you have running and for enhanced applications it will remember which documents those applications have opened, their position on the screen, and many other things - all with the push of one button. And to reopen all of these applications, documents, etc. you simply 'restore' the 'Work Set' - with either the push of a button or you can assign a hotkey(like F1 for example) so you can restore from any application at any time! This allows you to switch from project to project in an instant.