@The Pentacle Queen,
I have forgotten an embarrassing amount of facts about physics. By the way, this is one of the main reasons I so rarely post to the science threads. I'll will inevitably say, with fatherly authority and confident pulling rank, something completely bogus that will embarrass me for the rest of my life.
But I digress. Back to your question: The most enduring knowledge is the kind of thing ehBeth talked about. Knowledge about what sound reasoning looks like. A sixth sense for hidden bullshit, for gaps in arguments that would otherwise look impressive. Knowledge about how to get facts and how to interpret them in meaningful ways. I'm pretty confident that's the most important thing you'll learn in college too.