I would rather spend my time scrapping than tagging, so I have a VERY basic tagging scheme that works for me. I'm a kit scrapper most of the time - I rarely venture out of the kit unless there's really just one thing I need or whatever.
My system is to change the folder image to the kit preview. Then tag the folder with the year I got it, the store, and I do tag cards/alphas I can see myself using outside the kit. I label it KIT NAME - DESIGNER NAME.
I then file by
theme, not by designer. With my mac I can pull up any of the tags within a theme, so I can find things if I need to for challenges, etc. and know where I got them. I find I use things better this way, and I don't lost things.
Template - I only keep the TIFF tiles, and I rename them to be NAME - DESIGNER 01 (02,03,04 etc). I then tag them with store/year, and file them by photo spot.
All this takes less than 1 minute - between unzipping, renaming, putting the preview as the folder image, and tagging those couple of things. It works for me to keep me organized but I can spend more time scrapping then instead of organizing.