The major thing that I would like to see are better HTML controls. AFAIK, since HTML is everywhere in the OS now, why wasn't it a larger part of the .NET framework COM Interop works, but it has such an ad hoc feel to it, not to mention that IE's COM is bloated to begin with.
Who needs a Hyperlink control if labels natively supported HTML (or, most likely, XHTML, but whatever) What about, say, text boxes (even just "view only" like using the Rich Text Box in VB4), list boxes, and combo boxes As for the Rich Text Box, that is so 95! Escape codes are so last millenium. Even Help has switched from Rich Text to HTML.
HTML, or a derivative, IMO should be the base formatting method for nearly everything. Other things should be XML derived, like the Shortcut Key Underline Thingy. The Ampersand is being used more and more in Filenames and Folder Names, but it would be unlikely for any label to use <win:shortcut>, or whatever XML Namespace you felt like using...
Anyway, I would assume that Internet Explorer is getting its .NETization alongside Windows.NET (or whatever Nickname of the Month), and I wish y'all luck.

IE.net?
Jerry Langley
I was also thinking it might be interesting to have "CSS for Applications" allowing is to throw CSS tags into the beginning of an application to have Windows skin it like IE would, something like:
Button { button-style: flat; }
Button:hover { button-style: 3d; }
--WorldMaker--
Clive Greenhalgh
Paola B.
What I'm talking about is a XML browser that can render things like, XHTML (for layout and linking), Scalable Vector Graphics (for the majority of graphics), SMIL for animation and Multimedia support, CSS (for styling), and XSLT (for transformations). It is very similar to the X-Smiles project (www.x-smiles.org), but for an OS and/or brpwser (not Java).
IE can protoype some of this now, thru the use of behaviors, but the implementation is very old (pre XML), so it really doesn't have one document tree, but many document trees that overlay each other. I've got some examples up on the web if anyone is interested.
The SharpVectorGraphics (aka SVG#) open source project (www.sharpvectors.org) is working on achieving these goals, starting with SVG. You can see some of what can be done in the Developers section. Thru my work with SVG# I've run into lots of folks (including MS) that are interested in the same thing. Basically, an XSLT that can convert WinForm resource files to an XML document (with a couple different namespaces), and a OS/XML Browser that can render the document and call the code-behind functions as needed.
Don XML
yudkovsky
My vision for such a TextBox is that it will be used largely for formatting. As such I don't think support for client scripting and the like is really necessary, although perhaps it would be interesting for it to be able to host <input type="button"> controls which trigger events in the host container. I think it should also be able to contain hyperlinks. But largely I would love for it to support HTML formatting tags and CSS2. I would like to be able to access the contents via both DOM and by direct HTML, which will be fully W3 compliant (heh, wouldn't that be nice.)
I would also love to see HTML supported more in standard Windows functions in general, for example MessageBox, which would be translate to more functionality in all toolkits including .NET:
int result = MessageBox(hWnd, "<font color=\"red\"><BOLD>Fatal Error!</BOLD></font><BR><A href=\"http://www.microsoft.com/err.aspx&code=25\">Click here for details</A>", "<BOLD>Fatal Error</BOLD>", MB_OK | MB_ICONSTOP | MB_APPMODAL | MB_FORMATHTML);
Yeah, I know, tall order, but I can dream, can't I :)
* Yeah, I know BOLD isn't an HTML tag but B and STRONG were kept intact and would display as bold so it didn't work in my example.
Manip