PEiD (short for PE iDentifier) is a well-known professional packer/cryptor/compiler detecting tool. It's so powerful that it can detect the types/signatures of almost any PE file packing tools (at present, the number has been more than 600 kinds). In addition to the official version, AppNee also provides you its full-plugin version, which can be treated as the most perfect one version (contains 60+ plugins and necessary runtime library files: mfc70.dll, msvcr70.dll, rtl70.bpl, vcl70.bpl) on the Internet at present. I do believe reverse engineers or software cracking/unpacking enthusiasts must like it very much.
PE Explorer is an extremely powerful visual resource editor for 32-bit executable files (including EXE, DLL, DRV, BPL, DPL, SYS, CPL, OCX, SCR, etc.). It enables you to directly view, modify all kinds of resources in these files, which include menus, dialog boxes, strings, and so forth.
Decompiler and disassembler are essential tools for any sharp-sighted programmers. No matter which programming languages, they have their corresponding decompilers. For compiled Java binary class file, there are two excellent decompilers: they are freeware Java Decompiler and commercial software DJ Java Decompiler (AppNee will release its related resources later).
OllyDbg is a professional 32-bit assembler-level analyzing debugger from Germany, written for both Windows 32-bit and 64-bit, released and kept as freeware. As is known to all, it is really an edge tool for software cracking, and a must-have tool for many novices.
IDA Pro (short for Interactive DisAssembler Professional) is an excellent and extremely powerful decompiler with high efficiency and good interactivity from Belgium. It's also the best static decompiler at present (we can call it the world's top-level). Many programmers and more crackers use it and even can't do without it.