How about Schoolhouse? It’s very Mac-like with a clean but feature-filled interface that is organised around keeping track of your classes and coursework.
You can tell it’s designed by a student ‘cause it has everything you need – weighted grade tracking, places to keep your group contact info, and it even allows attachments to keep your homework in one place. Best of all it’s free!
I personally am going to try using OmniFocus which is a more general task/project management program based on the Getting Things Done philosophy (although you don’t need to be familiar with it). I’ve already been using it for all of my work/life stuff and while I liked Schoolhouse I found that hiding all the work into one program just made it more intimidating and easier to ignore. OmniFocus is really good at just showing you the little steps you can get done rightaway, chipping away at those big projects so I’m not running 48-hours sessions with ramen soup all over my keyboard.