For example, the Fossil purse I finally decided on has turned out to be the perfect bag. It's the perfect color (black), size (a paperback book), and material (corduroy), and has an extraordinarily useful strap. It's made to function like a belt, with metallic-ringed holes, meaning I can clip my keys through the bottom one and easily flash my electronic key anywhere I need to. (It gets us into the dorms and academic buildings plus acts as 'payment' for meals.)
Other things I've been glad to have: packets of trail mix, Dad's pocket-sized camera, my bike lock (which I crammed in at the last minute), my little notepads, my iPod headphone remote extension, and the black Target boots we bought less than 48 hours before departure.
On the other hand, I inconveniently left my Old English and Its Closest Relatives textbook at home, even knowing I would probably be working on my thesis here. Duuuhh. I also debated for days over whether or not to try to squeeze in Rena's Promise, another pleasure-reading book, about two sisters in Auschwitz. I finally decided not to, and wouldn't you know... the course I've been assigned (if the Creative Writing waiting list doesn't come through) is focused on the Holocaust! Sigh. Also, I only have one American plug, therefore I'm not really using my iPod speakers much, since that involves unplugging the computer, and we all know I never do that. :) Since it's only four months, I could have gotten by without them. The jury's still out on whether or not I needed three sweatshirts, but somehow I think the answer is no, since I'm almost certainly going to end up buying a UCU one before the semester is out.
One last random comment which has nothing to do with any of the above: I have discovered Firefox and plan never, never to go back to Internet Explorer.