Explorer Suite!

PE Explorer lets you look inside a variety of different 32-bit Windows executable file types, such as EXE, DLL and ActiveX Controls, perform static analysis, reveal a lot of information about the function of the executable, and collect as much information about the executable file as possible, without executing it. PE Explorer provides functions for disassembly and inspection of unknown binaries, modification of the properties of executable files, plus resource editing and translation features.

ILSpy is the open-source .NET assembly browser and decompiler.

What's Cool about dotPeek?Decompiling .NET 1.0-4.0 assemblies to C#Quick jump to a specific type, assembly, symbol, or type memberEffortless navigation to symbol declarations, implementations, derived and base symbols, and moreAccurate search for symbol usageswith advanced presentation of search resultsOverview of inheritance chainsSupport for downloading code from source serversSyntax highlightingComplete keyboard supportdotPeek is free!

JustDecompile is a stand-alone, free decompiling tool which converts assemblies into source code.

.NET Reflector is a class browser and analysis tool for .NET. It allows developers to navigate, search, disassemble and analyze .NET components.

Packer, compressor detector / unpack info / internal exe tools.

Free Zend Guard decoder, Free Java class decompiler, Free Adobe Flash swf decompiler, Free .NET (Dot NET) decompiler

GrayWolf is a .NET Decompiler that can edit the IL of a compiled .NET application. This Decompiler is targeted at hacking compiled .NET applications. This is a Beta product the IL editing is lacking and the deobfuscator is just getting going.