Welcome! I hope you find your iPad as useful as I do mine. For basic productivity tasks, check out Documents to Go to allow you to work with Office files. Also check out Goodreader, which opens pretty much any document format you can throw at it and has a file manager built in. If you've not tried it, give Dropbox a try. It gives you a 2GB cloud storage space that you can sync among your various computers. It integrates well with the iPad.
As far as use in the classroom, I use Keynote for giving presentations during trainings. I assume that you have picked up--or plan to pick up--the VGA adapter if you plan to use your iPad with a projector. I like it, but it only works with certain apps that support video out. I use an app called Notetaker HD that allows you to use your iPad and projector like a virtual whiteboard. You can save what you have drawn and you can import and mark up PDFs and pictures. The "inking" while using VGA out has a very slight lag, but it still works well. I use it all the time when I have meetings or conduct trainings.
Hope this helps. If you try out any of my suggestions, let me know what you think.
