Opions?

[ZiNgA BuRgA]

I rambled a bit, but basically, was wondering how to implement a default thread filter in forumdisplay.  Main issue being whether or not (and how) a user can override or disable this default filter.
For example, imagine a support forum where threads can have a status of "open" or "closed" (different to closing threads).  Perhaps you may only want open threads to displayed by default, so you could set a default filter on that forum.  But you also want the user to be able to view all threads too, so there needs to be a way for the user to disable this default filter.

Thanks for your opinion on the second thing