My top picks are the following apps:
Skype
ITunesU
RefScanSM
ReferenceMe
DropBox
Skype is important to me and I feel in general as a student as it allows you to connect and video conference with fellow students and teacher assistants and so forth.
ITunesU has a wealth of learning material available.
RefScanSM and ReferenceMe are useful tools when trying to write a paper and you're doing research on sources.
DropBox is an excellent way to share files with classmates as well as to backup the projects that you work on.
