I always smile when I see posts from people who have a "!Today" or "!On Deck" or similar context and who go on to say that they don't think it fits in with GTD.
I think you are very wrong for the following 2 reasons:-
1.In Getting Things Done David states that you should start each day by imagining what a great day would be.
2.The 4th stage of workflow is "Review"
Surely the most pure GTD approach to these 2 activities is to write down your results?
Personally I have a "!Do" context list which contains the Next Actions that I have reviewed and decided as the next priority. I try to keep this list bounded by things I can today. I try and review daily and before each review move any incompletes from the "!Do" list back to the appropriate contexts. This way I am not creating a daily "must do" list and I am not setting permanent priorities.
I also try and include some fun things on each "Do" list ( I have a separate checklist to inspire ideas).
This may not be in the book but to me it is the most "GTD" type thing that I do!