Is it possibly to guarantee transactional integrity when storing information in a Sharepoint list (SP 2010)?
Underneath the covers a single SharePoint operation like adding a list item can involve multiple database operations and they will all be protected by a single database transaction. With that said, the product doesn't expose that transactional capability to you so that you can perform multiple SharePoint operations under the aegis of a single transaction. To be very safe, you'll need to implement very carefully coded error handlers.