In David Cumps’ blog there’s a nice article on boxing/unboxing. Nothing really new about that topic, but it’s well explained, so read it if you don’t know what he’s talking about. Another thing worth mentionable is that using Generics for collections is of course the easiest way to work around boxing problems, assuming .NET 2.0 is an option to you. See the C# Language specification 2.0 here for more information on that.