To me - this is truly one of THE killer apps for the iPad - EasySign. What does it do? It lets you use your finger and sign those documents that you received via email, save as a PDF and send the signed copy out via email. This means that no longer do you have to wait till you get back to an office to print out, sign, and fax (or scan and email).
Essentially - you are Getting Business Done quicker!! I do not know any of 2K's clients that could not utilize this. The app itself is free and includes 3 free documents. You can then buy the ability to sign 20 more documents (in app purchase) for $4.99. And they've promised a $9.99 unlimited document version will be available soon.
You can watch a demo below and find EasySign in the iTunes Appstore here.