According to this (http://scn.sap.com/docs/DOC-28656), the last version of the SAP Business One Development Environment was released against SAP 8.81 and Visual Studio 2010.
Last year, someone was nice enough to compiled it against SAP 9.0, and make it available here http://sourceforge.net/projects/sapb1de/.
Is there a version of the SAP B1 Development Environment available for SAP 9.1 and Visual Studio 2013?
If not, is the B1DE still the recommended way to build SAP Addons? What are the alternatives?