Most, if not all, of my time finding threads is spent browsing the results from the "today's posts", "my posts", and "unanswered threads" links.
I like the "today's posts" link since it shows threads in which someone posted in the past 24 hours. So, you can see all the new, current, and randomly bumped ancient threads.
The "my posts" link shows me if there are any new posts to any threads which I have posted in before. Those new posts will also show up in the "today's posts" results, but sometimes the "today's posts" drown out the threads I've posted in, so the "my posts" link refines the search.
Of course, the "unanswered threads" links help me find people in need that I can help out.
The only time I don't use the links mentioned is when I'm browsing the classifieds or taking a quick peek for new posts in a specific forum.