Is vBulletin free and open-source?
No. PHPBB is tho and it's even better than SMF imho.
Why can't I see a list of all my started topics in a row? Whenever I want to find a topic I created I have to search for it or make sure I bookmark it after creating it.
I agree about PHPBB. I have run several boards (not nearly as active as this, though) for many years with PHPBB. I highly recommend it.