My iPad Essential Apps List for Grad students

I can't help it, but I have fallen in love with my new iPad. I think it's a perfect tool for graduate students. Here's why:

• PDF Expert: I purchased several PDF readers and have to say that, for me, the winner is hands down PDF Expert. It's simple to annotate (and not too costly).  Then, to top it all off the new auto sync with my Dropbox!!! I am in heaven.  I can access my annotated notes from any computer via my Dropbox account. This is exactly the feature that all Grad students need. Many other features make this my #1 iPad App for Grad students. Besides, it's just better for the environment, too, when there's no need to print.
• Kobo Reader, Kindle, iBooks... you'll want them all. Shop around and you are sure to save some money on your textbooks.
• Evernote. A free app that will help you access your Evernote account and add new notes. I love the display of this app. It actually inspires me to take notes, just so that I can view them later!
• Install the Diigo Diigolet toolbar, and the new free App for offline viewing, you'll need that, as well.
• Mindmeister... I am a visual thinker and like this concept mapping app.  Once again, this App allows you to sync to your online Mindmeister account. I like that you can attach articles and links to your thoughts.
• I have recently added Instapaper to my iPad and love this app.  As I have the wifi (not 3G) version, Instapaper allows me to read webpages offline at a later date. Very practical. It also cuts down my Twitter reading time... I can just select Read Later and the page is automatically saved for offline viewing.
• I would also recommend Documents To Go (invest in the Premium version for 16.99) which allows you to view and edit Word documents and Google Documents.  Once again, this app allows syncing to your online Google Doc accounts... so important in my opinion.
• For notes, more and more I am enjoying my NotesPlus app. I like the email features of this app and if you email as a PDF to your Google Docs, no need for paper notes at all. There is also a very easy microphone feature on this app, which I have used and works very well!
• For listening, add TuneIn Radio app. Great value.
• Last but not least, Sudoku or Solitaire! It can't all be work, can it?

What am I missing?