I think the award for "coolest upcoming technology preview" for this year's PDC has to go to the LINQ stuff. That's "Language Integrated Query" if you haven't heard this yet. If I had to sum up the idea behind LINQ in a sentence it would probably go something like this:
"The ability to do SELECTs from any .NET list of objects, including Database and XML, using an SQL like syntax and compiler checks. Oh and it can be extended to other stuff."
While not very very precise, it's more understandable that way I believe.
So, here's a thought.
With LINQ, and particularly with DLINQ, you'll be able to write database SQL SELECTs using C$ or VB.NET code.
Now, consider this. with SQL server 2005 (Yukon) you'll be able to write stored procedures using C# or VB.NET inside the database. Right? Right.
You know where I'm going with this, right?
I can almost picture it now - some consultant somewhere is going to be SO thrilled to have their customer use all the new "cool stuff" and they'll end up writing DLINQ stuff inside a SQL 2005 Stored procedure using C#.
It is on that day, my friends, that Microsoft will have come the full circle between application and database technologies.
PS
Mike has an interesting writeup on stuff to think about with LINQ coming up (more interesting to VBers, but Csharpers will see some value as well).