Personally I find Eclipse a bit slow and bloated on *nix. But that might be down to my crappy hardware more than anything else!
My IDE of choice for C++ on *nix is Code::Blocks. It's relatively small, it's fast, it looks and behaves similarly to Visual Studio and it integrates and works really well with the native *nix compilers (gcc, g++, nasm etc). Code::Blocks also ships with C/C++ project templates for several popular graphics/GUI libraries (wxWidgets, QT, OpenGL, OGRE, GTK etc), which can help to get new projects up and running quickly with a mininmum of fuss.
Incidentally, if you're interested in developing applications using C++ and wxWidgets, then the 'codeblocks-contrib' package is another must-have for Code::Blocks as it includes the wxSmith plugin, which can aid rapid application development with wxWidgets.
The wxSmith plugin extends Code::Blocks allowing you to visually/graphically place wxWidget controls on dialogs and windows. The plugin then auto-generates C++ code in your project in a very similar way to Visual Studio. If you've ever done any MFC development in Visual Studio on Windows; you'll find that using wxSmith with Code::Blocks is very similar!