Most useful Linq usage ?

I was thinking about how exactly i am going to use Linq "in the real world" yesterday. For me it will be as a Karmencita replacement. Because, sadly, i have never had enough free time to implement joins in Karmencita. Syntax highlightning also helps :D.
But seriously i see DataBlock + Linq perfect for implementing large "in memory" (in the ASP.NET Session State Service) data caches. That's by far the best use i see for it right now.