Time for a new flame war, folks! This forum has become a bit drowsy, lately :)
I haven't posted this yet to the IDEA tracker, but I'd like IDEA to become an Eclipse plugin. Eclipse simply has a much better CVS integration. The CVS integration in IDEA would need much work to be done to become as good as Eclipse's. I also like the look and performance of Eclipse's UI.
The thing I miss about Eclipse is IDEAs features for working with and in the code. It's the refactorings, the intentional actions and the highlighting of unused and redundant stuff.
Why not replace the Java Development Tooling which is really crappy (For the next version - 2.1 - they have announced the ability to use keyboard shortcuts for frequently used commands - wow, what a feature) and use the good things in Eclipse : Team support, Plugin architecture, UI for IDEA.
And they are working on SWT for MacOS, so this can be no reason against it.
I don't fear that IDEAs identity will be lost by this step. IntelliJ still could bundle a big pack with the Eclipse plattform and the IDEA plugin and it shouldn't be that difficult to display the IDEA logo instead of the Eclipse logo at startup.
Another advantage would be that plugins developed for Eclipse could be used with IDEA. The availability of a plugin only for Eclipse would be no argument against IDEA.
I use IDEA whenever possible, but in some projects I am forced to use Eclipse. Eclipse is the only allowed ide there but noone will forbid me the usage of plugins I want to use.