I don't recall having seen this suggested before, so because I'm lazy and would rather move between forums with one mouse click rather than two...

Add a quick link bar to the other forums, if not to all forums then at least the most commonly used, somewhere on each forum page and within the pages containing the discussion. Top, bottom, side- I don't really have a preference where.

My index finger will thank you.

Maybe a drop down before the Search forums button? Like a Quick Jump [Forum Name]

I think you're being a bit lazy there mate :P

I resemble that remark