Evan’s Data has release another IDE market survey from November 2005. This survey is free to download, so everyone can take a look.
An interesting thing about this survey is that it includes more than just Java IDEs. Microsoft Visual Studio comes out on top, in terms of share, but Eclipse is second, followed by Macromedia Studio MX. There is a quote from the study that claims Eclipse is the fastest growing IDE; although I am not sure how that was measured.
The report also ranks the IDEs by different features and then provides an overall relative ranking. IBM Rational Developer is top, followed by Borland JBuilder and then Sun Java Studio. Eclipse was seventh in the relative ranking.
It is worthwhile taking a look at the report.