Frames aren't completely worthless.

For example, vertical page centering is still impossible in CSS but extremely simple using a frameset.

Don't get me wrong, I'm notorious at work for destroying anything built using nested tables and restructuring it using CSS completely. CSS is very useful and extensible, and you should embrace it whenever possible.

But as a designer, you should be aware of all your materials, including less valueable ones like frames. You never know when you might need it.