First of all, you should know the basics. Than I would recommend you to concentrate on JEE (JEE 5) and its related web programming. EJB 3.0, AJAX, JSF, Spring, the comming Struts 2.0 are in this time pretty hyped.
The best way to find out what companies are looking for in your particular job market is to study the jobs offered section in relevant web sites/newspapers.
In the long run, you'll have better job satisfaction if you concentrate on areas that you are actually interested in, rather than solely focussing on what companies are looking for. That depends somewhat on the condition of the market you're looking in, of course.
And as suggested before, become proficient in the basics before tackling enterprise development.