Having switched to .NET 3.5 and VS2008 I've recently starting using Linq, and it's really cool.
But it seems to me MS has really screwed when it comes to maintenance. If you use the Linq SQL integration, generating code from a database is really easy. You just pull stuff into the designer, and magic happens. The nasty bit is that if you later change your database schema, you're basically screwed. Your only option is to delete the designer file and do all that dragging over again. That's a pain in the ass if you had to rename things, which is usually the case.
The Visual Studio team -- by creating a tool which is virtually useless in it's default mode -- has left the market wide open to the clever people of JetBrains. It seems the Linq team has committed the same blunder. Or maybe they don't care, I don't know. But still, maintaining Linq based code will be really painful, and for us non-consultants who actually care about our software after we've released the first version, this sucks.
Therefore, dear JetBrains, I hope you will put your brilliant minds to work and make Linq usable, just as you've made VS2008 usable. Maybe you can do this for ReSharper 4.5, or perhaps create "ReLinqer"? I'm pretty sure there's a big market waiting for you here :)