>There are a lot of good choices, but IMHO the best ones aren't open source.

Did you try Aptana Studio? I used it some (long) time ago and I liked it, but I used it superfically... here there is a review

>
>I concur with Craig - Visual Studio has one of the best HTML editors in terms Intellisense and extensibility support (especially with WebEssentials installed). It's quite excellent.
>
>I also really like Web Storm from JetBrains which has a similar feature set.
>
>The cool thing about these tools is that they provide a bit more than just an editor - from better Intellisense to tooling setups for creating projects, integrated debuggers to run your code etc. They have project templates and syntax expansion templates for various languages, dialects etc. For example, both Web Storm and VS have support for Angular syntax, directives and model intellisense inside of HTML. Web Storm is also cross platform and it runs on Windows and Mac which is a bonus and it's cheap (I think $89).
>
>A lot of people also use Sublime text, which is an excellent and extensible editor, but it also isn't free (although you can probably get away with it).
>
>I use all three of these on a regular basis. For pure HTML/JS projects (no or minimal server stuff) I tend to use Web storm. If server stuff is involved I use Visual Studio.For quick and dirty editing from explorer or small spot checks I tend to use Sublime.
>

[update]I gave the link to angular... sorry, but it appears as there is a plugin for angularjs[/update]
[update2]https://github.com/angelozerr/angularjs-eclipse[/update2]