Hi,
As tuanpham said, there is no recommandations.
JBoss Tools is a good tool to develop portlets. It allows you to easily create and develop JSR 286 portlets or JSF portlets.
If you don't use Eclipse, I know that NetBeans provides a tool for portlets called Portal Pack (but I have never tried it).
About the language, once again I don't think there is one better solution over another. If you already develop your applications with JSF, it would be a good choice to use JSF portlets. JBoss Tools is good in this case, you can easily develop over JBoss Portlet Bridge.