>If anybody done any work or some research of developing a business application for iPad, I have a question. I have two options (at least I can't think of others now): 1. Using MonoTouch from Xamarin develop a native iOs/mobile application or 2. using HTML5 with ASP.NET creating a web application. Which approach would you recommend? TIA.

A critical factor to consider:
Do you need the app to work when disconected?

Look seriously at Appcelerator Titanium.
We have been having good success with it for iPhone, iPad, and Android apps.