I use Websphere Application Developer (WSAD), which is built off of Eclipse and I love it. It is a memory hog (384-512 to run smoothly) but it's very nice to develop in and it has it's own test environment and such. Then again I usually am developing web apps so I need the test server, data sources and such set up to work with. I've developed some stand-alone apps as well in it and it seems to work well. Of course, I primarily use Java for my job, and I know how much you love Java.

I don't know how well Eclipse works for C++ but from what I've developed in it with Java, I do enjoy it.