Best Practices

For More Info http://mindsharpblogs.com/ben/archive/2008/11/06/11316.aspx

Fetch SharePoint Data Programmatically

There are different ways to fetch data in Share Point. SharePoint uses CAML to query the data. Following are the possible ways to retrieve the content
FullTextSqlQuery - search
SPListItems and for each loop - object model
List Web Service - Search from remote client
SPQuery Object - Search the list
SPSiteDataQuery - Search across the site
PortalSiteMapProvider