There aren't too many changes from C# 1.1 to 2.0, mostly improvements. Especially if you havn't been using C# in any form of profesional environment. The .NET framework has undergone some changes so there will be some differances. But the language itself is still good. If you were able to program with 1.1 you will have no problem with 2.0. There are a few added features you may want to pick up on like partial classes. But I dont see this being to significant to GameDev. I've been using the latest MDX (march release) for any GameDev I do (mostly small demos)

Unfortunatly there aren't too many good books on C# game dev especially for 2.0, but check the net there are plenty of resources. msdn.microsoft.com/coding4fun/ has some good 2.0 game dev stuff. check it out.

You'll be fine. However a lot of new features are incredibly useful and should be leveraged. (preferring System.Collections.Generic to System.Collections comes to ming.)

Just use your book while keeping an open eye for ways to leverage the new 2.0 features. The changes to the language itself are purely additive. There are some minor breaking changes in the class library.

1) Anyway, so if I want to program in C# now, should I use this C# 2.0?
A) I'd recommend it but only because most of the new features of C# 2.0 are there to help the programmer; to make his or her life easier. Generics are especially useful.

2) If so, is it necessary to buy Visual Studio 2005?
A) No. Download Microsoft Visual C# Express. It is currently free of charge, requiring you to register with Microsoft but nothing more. You could also use SharpDevelop as your IDE; the actual C# compiler is contained within the Framework that you download so if you wanted you could use Notepad to write your code.

3) And are there any radical changes in C# 2.0, or just added features?
A) There's two parts to what you're asking. C# 2.0 is the language and it consists of just added features. However, along with C# 2.0 is the 2.0 release of the associated .NET Base Class Library - think of it as the standard libraries provided with C++. Some of the changes in .NET 2.0 are breaking; few, if any, will affect you.

4) How about 2D and 3D development? What should I use?
A) Managed DirectX will probably be your best bet but the Mono Project does have OpenGL support through Tao.

5) Is there anything like SDL for C#?
A) Sure. SDL.NET is a wrapper for the SDL libraries for use within a .NET compatible language.

6) And is there OpenGL for C#? Or should I use MDX?
A) There's the aforementioned Tao and several other wrappers for C#. If you Google for "OpenGL C# Wrapper" you'll find plenty of hits - Tao seems to be the most supported/recommended.

7) Finally, what's the best book on C# 2.0 and game development with it?
A) Isn't one. I own just about every book on C# and game development and they all lack in one way or another, IMO. I've got one that has "Game Development with C#" in the title but doesn't even touch upon DirectX or GDI. (Yes, text is a more than viable method of presentation for games but I don't think a book should have that title if text is as far as it goes.)

8) I have lots of different books on the old C#, will they still apply in the new one?
A) Yes, certainly. If you're using the source from those books you may occasionally get an error about a method you're using being deprecated. At that point you may want to do some research and figure out the "new" method, but the old will still work. (And you can turn off the deprecation warnings if you'd like.)