v3 has some different template info, and as I'm sure more and more folks will be looking at customization in SharePoint 2007, I thought I'd lay out what the Microsoft templates are so that you don't end up creating any custom ones using our templateIDs.

Here's the list:
  ID - FOLDER (extra info)  -  Configurations

    0 - GLOBAL (SetupPath=global) - "Global template"
    1 - STS - "windows SharePoint Services Site", "Team Site", "Blank Site", "Document Workspace"
    2 - MPS - "Basic Meeting Workspace", "Blank Meeting Workspace", "Decision Meeting Workspace", "Social Meeting Workspace", "Multipage Meeting Workspace"
    3 - CENTRALADMIN - "Central Admin Site"
    4 - WIKI - "Wiki Site"
    7 - BDR - "Document Center"
    9 - BLOG - "Blog"
   20 - SPS (OBSOLETE) - "SharePoint Portal Server Site"
   21 - SPSPERS - "SharePoint Portal Server Personal Space"
   22 - SPSMSITE - "Personalization Site"
   30 - SPSTOC (OBSOLETE) - "Contents area Template"
   31 - SPSTOPIC (OBSOLETE) - "Topic area template"
   32 - SPSNEWS (OBSOLETE) - "News area template"
   33 - SPSNHOME (SubWebOnly) - "News Home template"
   34 - SPSSITES - "Site Directory area template"
   36 - SPSCOMMU (OBSOLETE) - "Community area template"
   38 - SPSREPORTCENTER - "Report Center Site"
   39 - CMSPUBLISHING (SetupPath=SiteTemplates\PUBLISHING) - "Publishing and Team Collaboration Site"
   40 - OSRV (SetupPath=SiteTemplates\OSRV) - "Shared Services Administration Site"
   47 - SPSPORTAL - "Corporate Intranet Site"
   50 - SRCHCEN - "Search Center"
   51 - PROFILES - "Profiles"
   52 - BLANKINTERNETCONTAINER - "Internet Presence Web Site"
   53 - BLANKINTERNET - "Publishing Site", "Press Releases Site", "Publishing Site"
   54 - SPSMSITEHOST - "My Site Host"
   90 - SRCHCENTERLITE (SetupPath=SiteTemplates\SRCHCENTERLITE) - "Search Center Lite"
 6221 - PWA (SetupPath=SiteTemplates\PWA) - "Project Web Access Site"
 6215 - PWS (SetupPath=SiteTemplates\PWS) - "Project Workspace"
14483 - OFFILE - "Records Repository", "Records Repository"

Hopefully this will be of some use to someone.  Do keep in mind that most things you would consider doing in SharePoint 2007 that you would have required editing Site Definitions in SharePoint 2003 can now be done using features and even solutions.  The global template even allows for "stapler" features to be applied across all existing templates, although most things like custom lists/etc would be added simply with a "staplee" feature.