Last night, I attended MS meeting of "Overview of new Portal features in Microsoft Office SharePoint Server 2007". Although the workflow feature for document management sounds good to me, I have deep impression about a good feature of InfoPath 2007: One form everywhere!
Basically, you can design a form to deploy only once. If a user has InfoPath installed on his/her machine, the user will download and fill the form locally (smart-client version); if the user does not have InfoPath installed, he/she can use popular web browser to fill the form (browser version, slightly different from smart-client version); the user can even see the form on a mobile device.
"One form" makes development and business process much easier.