Eclipse, open source Java IDE used by WebSphere, keeps rolling ahead.  M5, the last 2.1 milestone release, is out and its got tons of little usability features (see its list of new and noteworthy features).  I predict that Eclipse will become the second most popular IDE behind Microsoft's Visual Studio, and the most popular among open source developers.  Its popularity will move beyond the Java community to include C, C++, Perl, Python, PHP, and others.