I've been distracted all morning, drooling over the C# 3.0 features.  First, I was upset that they would tease us with 3.0 features before 2.0 is even released yet (and it's still a little silly), but being able to download, play with them, and run them makes a world of difference.  Here's my favorites distilled for those who don't want to check it out.

• Tons of type inference stuff.
• List<int> list = new List<int>();
• becomes
• var list = new List<int>();
• I'm not sure how I feel about "var".  It makes it feel a little like javascript.  I can see how that makes the language less ambiguous, and three letters isn't that bad.
• Tons of initialization stuff
• Initialize any collection-type-thing like you would an array. (new List<int> {1,2,3,4})
• Intialize objects with a named-parameter feel (new Person {FirstName="Mark", LastName="Miller} //not a constructor)
• A few AOP-ish goodies with extension methods - This is extremely cool.  Add methods to string, or anything else.  Very sweet.
• "Fix" the anonymous delegate syntax with lambda expressions
• delegate(int x) {return x+1;}
• becomes
• x => x + 1
• This will be hard to approach for some, but I think it's great
• Anonymous Types - This is excellent for working with data where you don't really need a formal type, you just need to work with some data.
• Language Integrated Query - This is the grand-daddy of them all.  Query against objects, query against XML, query against relational data, query against anything!  All using first-class features of the language!  I'm pretty excited about this.

I'm dissapointed in the lack of first-class duck typing support (late binding).  Yeah, we get half-way there through the use of query and anonymous classes, but there's some scenarios where that seems like hammering a tack with a sledgehammer.

I'm really excited in the innovation I see in the CLR-world.  Sure, lots of the above represent old ideas, but the query stuff represents big innovation in that space that fits right in where the "hurt" is.