Most of us use click macros. Recently Qbox made the nice web-based click macro creator that measures your keypress rate and does comma timing for you.

http://www.dual-boxing.com/showthread.php?t=28912

Wondering if anyone out there has the LUA coding ability to write an in-game version of this. Maybe with a start/stop recording function. Only measures while in combat and after an instance or fight or whatever it will give you your keypress rate. Just an idea. Seems simple enough to accomplish for someone who knows their way around wow's LUA.