Consider the next scenario:

You want to have a generic class, to handle different types of primitive data, but also strings.

So you'd like to have something like this:

public class Manager<T>
where T: struct OR string
{
...
}

or maybe you'd like to handle objects and strings:

where T: (ISomeInterface, new()) OR struct

or even specify some specific available types:

where T: long OR int

or two possible base classes:

where T: MyGreatUserControlBase OR MyGreatWebControlBase

et cetera.

I'd like to hear comments about that (and suggestions to the OR sign - |, ||, ; or whatever). If the feedback will be positive, I might suggests it to MS guys as a ladybug or such, and we might see it as part of C# 3.0, or maybe 4.0?