Debugger
Ollydbg
Hex editor
Winhex
Disassembler
IDA
Function/API Monitor
Auto Debug for Windows
Memory Searcher
TSearch
Resource Editor
PE Explorer
File watcher?
Filemon ....of course
Well I'm fairly new to the "scene", so I don't use many of the old school tools, but I am learning

. A few of my choices were obvious picks (IDA, filemon ...etc). I haven't done much unpacking yet so that isn't on my list yet... I'm sure you guys have many more categories that I didn't think of.
Interested too see what other people like and use.