Recommended validating XML parser?

[Kirk Strauser]

We're looking for a current, supported, validating XML parser.  Since it
seems like there are a few thousand out there, I though we'd see what
everyone else is using.

Bonus points if it can do something like:

    >>> foo = XMLParser("""
    <xml>
        <weight>3000</weight>
    </xml>
    """, dtd=file('/etc/weightfile.dtd'))

    >>> print foo.weight
    3000

...or some variant on that theme.
-- 
Kirk Strauser