This is a book I've read 3 times now, and I still can't get enough of it. It's by far one of the best C# books available on the market today. Luckily, in the spirit of MMOwned, I'm hosting it for free.
Enjoy folks!
Pro C# 2008 and the .NET 3.5 Platform
It's 1300 pages long, so be warned. It's also a PDF so feel free to save it for your personal use.