I've been practicing GTD for over five years now and watch the trends carefully for various applications, programs, gadgets, etc. While I am continually impressed with every new gadget or program that comes out, I also wonder about the "tinker effect":
The better these programs and gadgets become, the more there is to "tinker" with (e.g. tagging, prioritizing, color-coding, organizing, etc). How do you know if a tool is going to help you get more done or whether you are going to spend endless hours re-arranging your stuff? Anyone had to abandon a good tool because they found themselves tinkering with their system more than getting things done?