What would be the best/quickest way to have a IDE-type setup when I have existing C/C++ source with several Makefiles (library, executable etc.).
I need to work with compiler errors in the IDE and preferably navigate the code.
In the past I have used Emacs/Xemacs, and it is OKish, but I am not sure about the best way to set it up.
The Eclipse CDT plugin is a pretty decent IDE for C/C++.
I've found the code navigation features good for small-to-medium projects (the indexer becomes slower with very large projects). Eclipse has its share of detractors for being bulky and Java-based, but it works fine for me.
KDevelop and Netbeans might be worth looking at as alternatives, if you want this kind of GUI-based IDE. As you've said, Emacs (or Vim) can be used to get the same functionality with more of a keyboard-based approach, with the right setup.