As opposed to some other guys here, I think that an IDE does add much to software development, even for a dynamically typed language like Python which makes it harder to do static analysis.
My preferred IDE for Python development is Eclipse with PyDev. Before that, I coded in Notepad++ which isn't much different than the PyDev editor in terms of features. PyDev has some great features that you won't find in a "normal" editor:
- It shows warnings and syntax errors (almost) in realtime. A text editor won't tell me about typos, but PyDev does. As another example, unresolved imports or undefined functions (e.g. because of a typo) are marked as warnings/errors. And there are many more common mistakes that are automatically detected, and PyDev can be integrated with pylint so that warnings and errors from pylint are displayed with the usual icons in the editor.
- Autocompletion by introspection
- Outline view of the current module and its classes
Additionally, Eclipse itself is also great for any kind of programming project. I especially like the fully integrated interface - project explorer, editor, outline, console, problems overview, run configurations and so on. When using Vim, Emacs or similar, I guess you would have to install lots of plugins or custom scripts to achieve the same.
As you said you want to do a project, I think that Eclipse is a good choice. For quickly hacking a small Python script, it's overkill of course.