XML Marker works well for Civ4, I don't know about Elemental because I'm not in the beta.

Notepad++

http://sourceforge.net/projects/notepad-plus/

http://sourceforge.net/apps/mediawiki/notepad-plus/index.php?title=Plugin_Central#X

Not sure if XML Editing is modified in Visual Studio Express compared with Visual Studio Ultimate, but if it is not, VS is a very good tool too.

Thanks for the suggestions folks!  Notepad++ it is.

Thanks to the power of YouTube, and the goodwill of numerous contributors, I got a good demo of it.  Was impressed by its simplicity coupled with a wide range of capabilities. And the idea of open source collaboration just makes me happy.  I hadn't known that all those scripting languages would be supported under one roof.  Among that list; XML, Python, HTML, Java and Javascript are things I've recently wanted to play around with.  And just for the fun of it, this post was written using Notepad++ :~)  I tried writing the HTML for it, but when I pasted it to the forums some of the tags were altered.  Is that because some other program like Javascript(?) is used for the reply box? 

Thanks for the Notepad++ recomendation! It's provided me an impetus to explore new horizons beyond XML.  And I'm finding the basic text editor (+ spell checker) to be useful already. 

I never had such problems with it when editing Civ4 files. But maybe it's because I didn't make any big changes using it, only changed a number here and there. I liked it because it allows displaying the data as a table, with sorting etc.

For bigger changes, like adding or removing entire entries, I used the standard Notepad (but Notepad++ sounds interesting, I'll try it when I need to edit XML files again).

Line

And boomed again

That would be your problem. Leave out the html and body and header tags and all of that. Every page should only have one body tag, and the forum already has its own body tag, which will eventually contain the post you submit.

 Now most html tags won't work in the editor, but you should be fine with <b > and <i > and some font tags.

The "insert code block" button is so you can write code and have it show up as plain text rather than actually doing the thing you tell it to.

Currently Quoting seems to break the HTML of the post you quote, leaving only BRs. (that didn't happen before) Try better viewing the source code of the page.

In the "Edit HTML source" you should be able to use the most common HTML tags(p, br, b, strong, i, em, u, table, tr, td, div, span...) and their properties (like style, for that so much needed CSS touch).

I hope that's what you were asking for.

some other REALLY nice apps are XMLSpy and LiquidXML.  Both of which are pro level apps and require some cash investment.  I use these at work as well, but will often fall back on Notepad++.