I'm not sure how much you need to carry, but I love my North Face Ray 20. I'm fortunate to have a locker at work for my clothes, so all I haul is lunch, a couple of files, wallet, cellphone, and my laptop. It comes with a rain cover in a little pocket that works quite well at keeping everything dry.

Here's a link:
http://www.ebags.com/the_north_face/...modelid=100191