Prioritize Learning about LINQ
One thing I'd not invested enough time in was LINQ - I was at the PDC when we announced this stuff and saw it in the keynote and went to Anders sessions - but to be honest I was a little lost in the Lamda expressions :)
Well I've stayed out of it for too long and I forgot just how AWESOME LINQ actually is - it's going to change the way people write code on our platform with a O/RM that we ship and fully support with tools.
ScottGu has a series of great posts on his blog with screen shots and step-by-step walk throughs to help put it all in context.
If you write code get ready for a change in the way you work - for the better, language innovations like LINQ don't come along that often. We have worked on this stuff many times before and always pulled it - LINQ is for real and we have a great ed to end scenario.
All I can say is take the time to learn LINQ every developer will want to know about it.
The Official LINQ project page on MSDN.
Note to self: we need to get out there and talk more about this.