jQuery .is(':checked') always returns false
<p>No mater if the radio button is checked or not, .is(':checked') will return false.  Here is some stuff I was playing with in Chrome's console while I was debugging this:</p>

<pre><code>&gt; $('#blah')
[&lt;input type=​"radio" id=​"blah" name=​"blah_type" value=​"blah" class=​"styled" checked=​"checked"&gt;​]
&gt; $('#blah').removeAttr('checked')
[&lt;input type=​"radio" id=​"blah" name=​"blah_type" value=​"blah" class=​"styled"&gt;​]
&gt; $('#blah').is(':checked')
false
&gt; $('#blah').prop('checked', true)
[&lt;input type=​"radio" id=​"blah" name=​"blah_type" value=​"blah" class=​"styled"&gt;​]
&gt; $('#blah').is(':checked')
false
&gt; $('#blah').prop('checked')
true
&gt; $('#blah').removeProp('checked')
[&lt;input type=​"radio" id=​"blah" name=​"blah_type" value=​"blah" class=​"styled"&gt;​]
&gt; $('#blah').attr('checked', true)
[&lt;input type=​"radio" id=​"blah" name=​"blah_type" value=​"blah" class=​"styled" checked=​"checked"&gt;​]
&gt; $('#blah').attr('checked')
"checked"
&gt; $('#blah').prop('checked')
undefined
&gt; $('#blah').is(':checked')
false
</code></pre>

<p>What could be going wrong here?  I'm using jQuery 1.6.4. </p>
