I tried early versions of Eclipse. They sucked.

Eclipse 3.0 is a huge improvement. (And the performance problems seem to be fixed.)

Eclipse Distilled is a fast 280 page tour of Eclipse and, while Java coverage is a given in an Eclipse book, Eclipse is clearly…

·         A platform – not a tool.

·         Not intended only for Java Developers

 
The books gives you a good insight into the open nature of Eclipse and the breadth of plug-ins that are available for Eclipse 3.0

It’s a long way from Visual Studio .NET. Here are my tools of choice.

Windows .NET and C++ Development – Duh ! Visual Studio
Except when I work in PHP, then it’s Zend Studio
For COM specific work I’m using either Delphi 2005 from Borland or VB 6.0
When I do Java work on Windows it’s Borland’s JBuilder 2005

But….  When I have to do C, C++, or Java on Linux (Ewww – for interop demos ONLY) I think it will be Eclipse.
If you’re a Java developer and new to Eclipse or wanna understand the Eclipse tool phenomena – this is a very good, quick read.