Add-in recommendation for displaying code in a post?

I searched and found a lot of Wordpress addins/widgets for displaying code in a post and was wondering if there are any recommendations? I need to be able to show XML, C++, C, C# primarily. F# and Haskell would be nice but not essential.

Update: Also should be able to use Windows Live Writer when posting the code. Am I asking for too much here? :)