Jakarta Commons (http://jakarta.apache.org/commons/) is a similar idea, but for Java. I found the Collections and Lang components particularly useful.

I was surpised there wasn't something like this when I started in .NET.

I think this is an awesome idea!  I definitely have a growing "bag of tricks" that I use on almost every project and have yet to come up with the best way to manage it.  Here are a couple of ideas I have (and I am definitely willing to help out):

1. As you mentioned in your post: A Common Root namespace with all sub sections in their own sub namespace.  Example: Common.Data, Common.Xml, Common.String, Common.Math, Common.Html, Common.Sorting, Common.Collections, etc...

2. Maybe make them available as one assembly or in seperate assemblies (assuming you can prevent each "package" from being dependant on each other.  It would be nice to be able to use just the string methods without having to also include the Xml methods etc.

3. Require Unit tests with all methods/classes added/submitted to the library

These are just a couple of things but I can definitely see the awesome potential in this.

Heh.  For pure VB awesome-ness, try the utility belt:

http://www.learnasp.com/freebook/learn/utilitybelt_lib.aspx

I'd be willing to participate...have a decent sized utility class toolbelt that I use on a regular basis.

Prebuilt regular expression classes. For email addresses, credit cards, zips, phone #s, etc.

Sounds like a great project idea, we'd love to have it on CodePlex!

Awesome Idea.

What license would you consider using?  (GPL? BSD? Apache?).. just curious.  Consider that carefully as it impacts future use in various and sometimes unintended ways.

I would be interested in contributing.

Keep us informed of any progress.

I'd love to be involved in this as well!

The license needs to enable us to use it in non-open source projects and we need to be able to modify the code without any restrictions, imo.

I see that Microsoft is using Creative Commons quite a bit, perhaps that's a good starting point? BSD is another nice license, GPL won't work for us...

Just as a side note, the Genghis project provides a lot of functionality for WinForms: http://www.sellsbrothers.com/tools/Genghis/

Cool name btw.

I would love to participate in this as well! I know of others who would also be interested!

This is a top idea! I, like everyone else, have a common lib project that I port to every application I use.  I'd love to help out in any way I can.

I am willing to participate as well.

By the way, does any one know why im not allowed to post at devlicio.us?