I use Emacs. Ostensibly, it's a text editor. But for some languages, it's essentially an IDE. For example, I use typerex for OCaml which takes advantage of OCaml's type system to provide a bunch of high level features like showing errors in the code, auto-complete and some refactoring.

My main point (apart from the fact that OCaml and Emacs are awesome) is that there is no clear delineation between text editors and IDEs.