Yes, I'm a little behind times. Up until just a few weeks ago NetTiers has been what I have used as a data layer in almost all of my little projects, and even some of the larger ones. But I recently made the jump to LINQ. And now, I feel not very smart because I waited so long. I was expecting the learning curve to be in some way difficult, but to my surprise, there was no learning curve.
I've started and am almost complete converting www.elementoffear.com over to use LINQ now instead of the NetTiers layer it has been so happily using. ScottGu's Blog has a great guide to get started down the path. The tricky part for me was the connection string being different in my staging environment and production environment, but it was easily overcome after a quick Google search.
I am now in the process of migrating some very old, and as much as I hate to admit this, sites that use datasets to using LINQ now. I am impressed with the speed and actual low resource usage of this Microsoft product. Everyone go and read up on it and start using it!