IDA is a powerful multi-processor disassembler and debugger.
With this program you can disassemble your 32/64bits Windows executables.
Microchip PIC18 Disassembler is a tool for the PIC18Cxxxx and PIC18F parts only.
Disassembles and debugs multiple targets and handles remote applications.
NoICE is a debugger for microprocessors useful for many targets.