Although my commute is not that far I just ride in regular clothes. My pedals are Wellgo somethings and I just use Power Grips. Whatever accesories you do get, just make sure they are portable (lights, rear blinky, air pump, seatbag, etc.). Something you can stuff in your backpack once you are locked up.

I think a rear rack and fenders would serve you well. You could probably bungee your backpack to the rack instead of keeping it on your back (shoulder straps up). You could also look into those panniers that double as a backpack as another poster mentioned (though I heard the attachment system can dig into your back). If you go with a backpack I would suggest one slightly larger than what you would normally carry (for extra stuff) with a waist/hip belt, chest strap, and perhaps internally framed.

Check with your campus police if it has a high incident of bike thefts. Some campuses are notorious while others rarely anything happens. A good ulock for the rear triangle and tire and a cable for the front wheel may be sufficient. Also LOCK your bike in a well traveled, lit, and secure place (our campus just intalled a bike rack with an overhead very close to the quad ). Otherwise get to know some of the professors or others who bike to work. They may let you park your bike in their office, a classroom, or an unused storage place. Also see about lockers and such. Some of our older buildings and Athletic facilities have them. Our Art Department has some huge ones.