Want download of entire Photo Stream and or Camera Roll from iPhone4S running iOS 5.1.1 to Win 7 Enterprise SP1?
In a nutshell...


Connect iPhone to iCloud.
Configure PC to connect to same iCloud account.
Select Photo Stream and click the Options button.
Configure your Upload and Download Folder, and Select the Photo Streams you want to sync.
Your photos should start to sync at this point; check My Computer | Libraries | Pictures.


This setup works for me on Windows 7.