Respectfully, I don't agree with your conclusion at all.

• Emacs/Xemacs run fine under X in a windowed app. I don't know why you would assume they don't. I can't speak to vim because I don't use it much.
• Most linux distributions have a *real* web server and multiple database options installable right from the install CDS. Part of an IDE is being able to debug/run code in an environment that simulates your production system, and if you host on linux you can't get much closer for your development systems then the same OS, and probably the same distribution.
• Fundamentally: when you use linux (or any other *nix, really) to develop the whole OS is your IDE. You've got your choice of shells (that aren't crippled like Win32), source code control, file syncing via rsync, useful documentation at the shell, you can tweak your web/database server settings for testing right on the system you're developing on and you have access to pretty much everything that effects your application.

Different strokes for different folks. I personally don't need an editor to do everything but wipe my butt for me, because my OS is my IDE.

Edit: This is in reponse to justsimple, NOT perrin.