Is it an app
This is a discussion on Excell & word within the iWork Forum forums, part of the iPad App Store category; Is it an app...
Rumors (and it is only rumor) say that Microsoft may be releasing these apps sometime in 2012.
In the mean time here are some reviews of the more popular Office compatible apps. Like Bob, I prefer Pages, but your needs may differ.
Compare iWorks, Office 2 HD, Documents to Go, QuickOffice by richsdams
Office Apps Comparison by RedCoil (details and examples, very long)
About QuickOffice, mostly about spreadsheets
Just purchased Quick Office HD...