My client required a google product feed representing their store products, so I decided to make use of Linq-to-Xml to generate the Xml markup and Linq-to-Objects to retrieve my product data.
Initially I had my doubts about using Linq, however, since seeing how efficient and clean the code was compared to using XPath, I'm now a believer ;)
Here is the code. Copy and paste this into a Test.aspx page.