Notepad (or pico on Linux) and a browser is the best programs you can get along with learning HTML, JavaScript, JAVA, PERL or PYTHON, XML, PHP, ect. I know other people are not going to agree with me but remember this. No matter how well a program is written, noone can write a progam that writes programs for any situation. You always wind up tweeking the code by hand so you might as well just learn the code to begin with and do it all by hand.
Just my $.02.

Hi Defledermaus,
You'll want to take a look at Macromedia Dreamweaver it is recognized industry-wide as the #1 web dev tool. Yes it's easy to use. Silver-Dagger is correct to a certain extent you will find it beneficial to know the interworkings of web languages. However at the same time that was spoken like true Linux user. Allow me to paraphrase what he said "It's easier when you know everything, so why not try to learn just that?".
Cheers,
Christian

Also using a plain text editor like Notepad, works but isn't nearly as efficient as a web development tool. If web development tools weren't significantly more efficient there wouldn't be a market for them, but obviously there is a huge market for them, so they must do something better than notepad:
-Syntax Highlighting
-AutoCompletion
-InCorrect Code Marking (Like spell check, but for code)
-Simplified Uploading/Downloading/Editing
-Speadier Creation of Complex Web objects like forms, tables, etc...
-WSYWIG (What you see is what you get) page creation [Like Microsoft Word]
-Et Al.