What tools can be recommended for automated testing of GUI applications on Windows?
The tools must be language-independent and thus should be able to interact with any GUI, regardless of implementation language. In other words, I'm looking for something that can be scripted to press buttons, select menu items, check checkboxes, etc., and ideally observe the results and compare them to reference results.
What are your experiences with such tools? Do they work, in practice? Are they worth the time they take to set up and configure? Do they actually find errors in the GUI or the application?
Update
I am aware of the replies to the other threads mentioned in the first answers, but I would like to hear from people who have experience with using these tools—or other tools—in practice.