The aftermath - what to do when the marathon is over!

In about 10 days time, I will have passed the marathon finish line (hopefully!) and with it should come an enourmous sense of relief that I have completed my training programme and marathon. But what next?
In the past, there has been a  sense of anti-climax when the marathon comes to an end which is totally natural. After 16 weeks of knowing what every day entails training wise, there is no longer a marathon to train for or routined training sessions to complete.
I used to take this as a chance to kick back, relax, pat myself on the back for way too long and eventually get back to training in a worse state of fitness..but not anymore!
Even though the effects of a marathon on your body can take a reported six weeks to fully recover from and it's not recommended to run for up to two weeks after crossing the marathon finish line, I intend to vary my training on completion of the marathon.
Maybe take to the bike, spend more time in the gym etc. or set another goal such as long cycle or triathlon or improving my times at shorter distances (when I've fully recovered) as I've felt that the sense of routine to my training was a positive thing and helped my focus on my fitness.
Either way, unlike years gone by, I won't be transferring to the couch with the tub of ice-cream vowing not to move until the physical and mental scars of this years marathon heal!