For a complete c++ IDE, I like NetBeans. It is much easier to import an existing Makefile-based project into Netbeans than Xcode or Eclipse, the editor is completely customizable, and the code completion and navigation are simple to learn. TextMate is also great for quick editing of files and has an excellent interface for the Find in Project command.
And, the Aquamacs implementation of Emacs for the Mac is fantastic. Like vim, emacs has a rather steep learning curve but is a very powerful editor for c++ development. Using the Emacs Code Browser you can get most of the IDE functionality available in other options like Xcode or NetBeans.
As for other languages, I find Netbeans to be far superior to Eclipse for Python development. The hints, error checking, and library completions have really cleaned up my Python code. However, NetBeans is inferior to the Photran plugin in Eclipse for Fortran development. The Fortran support in NetBeans provides little more than syntax highlighting.