Got this little tidbit from Joe Picc today, which is a good way to get the XML that's getting passed to your XSLT in your SharePoint web parts:
After your <xsl:template match="/" ...> tag, add the following:
<xsl:copy-of select="." />
What gets returned is the XML that is sent to your XSLT, so if you need to check it out or debug with it you can.