When I started working for my current employers, they had standardized on IntelliJ-IDEA, which was a very good tool by comparison. However it cost a lot of money per person (some hundreds of dollars) and because we were cheap (or broke) we didn't upgrade at all. After a few years the tool was very out-of-date.
At that point 3 years ago, we decided to use Eclipse. IDEA would have cost too much when we had 10 developers. Eclipse had the tempting promise of being open source and more importantly free!
I must say it has lived up to the promise. It is a wonderful developer tool. The great thing about open source is that there are many plug-ins available that are really useful. Some are free, some are commercial, but relatively cheap.
The bad thing about open source is that things that work can get broken when you upgrade. For example I once had a really nice combination of Eclipse, Subversion (Subclipse) integrated with the Eclipse Navigator tool showing file decorations, version numbers, authors, dates, etc.. When I upgraded my Subversion client (Tortoise) a while ago, this all stopped working, in spite of many attempts to fix it. Pooh. Never mind.
One nice commercial integration is MyEclipse. I fell in love with this because of the jsp debugging (breakpoints!) and some nice XML editor features. Recommended. $30-50 per year and it's well worth it. They also bundle the full Eclipse download if you want it.
So, some free plug-ins I use quite often:
- ASDT (ActionScript Development Tool) because the Flash CS3 ActionScript editor is still
horrible (frustratingly so, considering the cost of CS3!)
- Implementors plug-in http://eclipse-tools.sourceforge.net/implementors/index.html
- Subclipse (although it's not working with my present setup)