What are these knobs for?

The top knob is the screw mechanism to tighten/loosen the QR clamp/
The bottom one is for controlling the ball head position.
Here's a picture (F3 is the second from left; others are Adorama's Flashpoint F2, Manfrotto 486RC2 and Manfrotto 488 with RRS LR40 release plate instead of the RC2 plate)

Thanks, that picture is really helpful Jon

So, the F-3 has three knobs? One for tightening and loosening the QR plate, one for tightening or loosening the ball, and a third for panning?

I don't expect to have more than a 5D2, and a 24-70L mounted to it. The day I have a bigger lens attached to the camera is also the day I can afford a new ball head

That'll hold a bigger lens. Here's the (smaller) F-2 holding (after an hour at that angle) a 1D3 and 70-200 2.8 IS. Note I'm not using the tripod mounting ring; that's fastened to the camera, so you're seeing more torque than you typically would.:

Good to know I'll be set for a long while! Super helpful photos, thanks!

There are three knobs, correct? One for tightening and loosening the QR plate, one for tightening or loosening the ball, and a third for panning? Just want to make sure I know this ball head inside out be ordering

Right. Three knobs with the functions you describe.

I guess I'll be placing my order tonight
Thanks again for all the help Jon