I'm a big fan of ThinKiosk and the feature set keeps getting better and better. The preview of version 4.0 looks promising. Some of the new features include:
- Lock down
- Broker Service and Management Console
- Support for Windows 8
- Web browsing built in
- Windows keystroke blocking
- Auto login
- And a lot more!
Andrew Morgan and Remko Weijnen have put in a lot of effort on this and it's still free!