Here’s an example of great UX.  Error reporting and possible solutions are presented in SharePoint 2010 Central Admin thus:

Selecting an item in the list displays:

Key Points.

1) The categorisation of the lists.

2) The message in the list is human readable – not just some stupid error number and cryptic message.

3) The explanation of the problem is clear and concise.

4) The remedy is similarly understandable

and, best of all

5) The remedy contains a link to the solution

Wouldn’t it be fantastic if all products were so well designed?  How much more productive would programming be if Visual Studio worked like this.  eg:

Warning: You have a compiler error in a LINQ query with a join.  Click here for a solution.

Clicking would show the native compiler error, a few links to MSDN documentation, the top 10 web search hits for the issue and a link to see more in Bing/Google.

You could maybe also add in automatic refactoring, tied to code analysis rules or whatever.

Hey, how about this one:

Warning: The application you are creating has already been created by 12,875,435 other developers.  Would you like to download one of these instead?

:)