Return all values in XSL

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes" />
<xsl:template match="/">
<xmp><xsl:copy-of select="*"/></xmp>
</xsl:template>
</xsl:stylesheet>

Contextual Search Results

I wanted to configure a contextual search to bring back results from a particular list only and display the results on the same web part page. I also wanted to be able to open the results items in a modal dialogue box (new for SharePoint 2010). On my page I have:

1. a Search Box web part configured as follows: 
• Scopes dropdown: Do not show dropdown and default to target results page 
• Target search results page URL: /site/Pages/default.aspx
2. a Search Core Results web part configured as follows: 
• Results Query options / Append Text To Query - Site:http://site/Lists/ListName contentclass:STS_ListItem.
• Edit the Display Properties XSL by searching for this line:
  
  <xsl:attribute name="href"> <xsl:value-of  select="$url"> </xsl:value-of></xsl:attribute>
  
  and replacing it with this:
  
  <xsl:attribute name="href"> javascript:OpenDialog('<xsl:value-of select="$url">') </xsl:value-of></xsl:attribute>

Thanks to Glyn for pointing me in the right direction again and Rain Tree Studio for this list of contentclass values, which can be appended to a search query:

        case "STS_Web":                                       // Site
        case "STS_List_850":                                 // Page Library
        case "STS_ListItem_850":                          // Page
        case "STS_List_DocumentLibrary":            // Document Library
        case "STS_ListItem_DocumentLibrary":     // Document Library Items
        case "STS_List":                                        // Custom List
        case "STS_ListItem":                                 // Custom List Item
        case "STS_List_Links":                             // Links List
        case "STS_ListItem_Links":                      // Links List Item
        case "STS_List_Tasks":                            // Tasks List
        case "STS_ListItem_Tasks":                     // Tasks List Item
        case "STS_List_Events":                          // Events List
        case "STS_ListItem_Events":                   // Events List Item
        case "STS_List_Announcements":            // Announcements List
        case "STS_ListItem_Announcements":     // Announcements List Item
        case "STS_List_Contacts":                      // Contacts List
        case "STS_ListItem_Contacts":               // Contacts List Item
        case "STS_List_DiscussionBoard":          // Discussion List
        case "STS_ListItem_DiscussionBoard":   // Discussion List Item
        case "STS_List_IssueTracking":              // Issue Tracking List
        case "STS_ListItem_IssueTracking":       // Issue Tracking List Item
        case "STS_List_GanttTasks":                  // Project Tasks List
        case "STS_ListItem_GanttTasks":           // Project Tasks List Item
        case "STS_List_Survey":                        // Survey List
        case "STS_ListItem_Survey":                 // Survey List Item
        case "STS_List_PictureLibrary":             // Picture Library
        case "STS_ListItem_PictureLibrary":         // Picture Library Item
        case "STS_List_WebPageLibrary":             // Web Page Library
        case "STS_ListItem_WebPageLibrary":         // Web Page Library Item
        case "STS_List_XMLForm":                    // Form Library
        case "STS_ListItem_XMLForm":                // Form Library Item
        case "urn:content-class:SPSSearchQuery":    // Search Query
        case "urn:content-class:SPSListing:News":   // News Listing
        case "urn:content-class:SPSPeople":         // People
        case "urn:content-classes:SPSCategory":     // Category
        case "urn:content-classes:SPSListing":      // Listing
        case "urn:content-classes:SPSPersonListing":// Person Listing
        case "urn:content-classes:SPSTextListing":  // Text Listing
        case "urn:content-classes:SPSSiteListing":  // Site Listing
        case "urn:content-classes:SPSSiteRegistry": // Site Registry Listing

Grouping list data in XSLT

I used a linked XSL file to override the output of my list web part, grouped by one of my custom columns called 'Classification'.

To add in an XSL override link to your XSL file via the list web part properties:

XSL (uploaded to a SharePoint Document library):

<xsl:stylesheet xmlns:x="http://www.w3.org/2001/XMLSchema" xmlns:d="http://schemas.microsoft.com/sharepoint/dsp" version="1.0" exclude-result-prefixes="xsl msxsl ddwrt" xmlns:ddwrt="http://schemas.microsoft.com/WebParts/v2/DataView/runtime" xmlns:asp="http://schemas.microsoft.com/ASPNET/20" xmlns:__designer="http://schemas.microsoft.com/WebParts/v2/DataView/designer" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" xmlns:SharePoint="Microsoft.SharePoint.WebControls" xmlns:ddwrt2="urn:frontpage:internal" xmlns:o="urn:schemas-microsoft-com:office:office">
<xsl:include href="/_layouts/xsl/main.xsl"/>
<xsl:include href="/_layouts/xsl/internal.xsl"/>
<xsl:output method="html" indent="yes" version="4.0"/>
<xsl:template match="/">
<xsl:call-template name="MyTemplate" />
</xsl:template>
<xsl:key name="classificationKey" match="Row" use="@Classification" />
<xsl:key name="associatedTitle" match="Row" use="@Title" />
<xsl:template name="MyTemplate">
<xsl:for-each select="/dsQueryResponse/Rows/Row[generate-id(.)=generate-id(key('classificationKey', @Classification))]">
<h3><xsl:value-of select="@Classification" /></h3>
<xsl:variable name="thisClassification" select="@Classification" />
<xsl:for-each select="../Row[generate-id()=generate-id(key('associatedTitle', @Title)[@Classification = $thisClassification][1])]">
<div>
<strong>Title: </strong>
<xsl:value-of select="@Title" /><br/>
<strong>Description: </strong>
<xsl:value-of select="@Description" disable-output-escaping="yes" /><br/>
<strong>Link: </strong>
<a href="{@Link}" title="{@Title}"><xsl:value-of select="@Link"/></a>
</div>
</xsl:for-each>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

This is the output:

Classification 1

Title 1
Description 1
Title 2
Description 2
Title 3
Description 3

Classification 2

Title 4
Description 4
Title 5
Description 5