Well I guess mostly people have covered the major points... this is definitely unexpected and I think most here would agree it's likely going to feel like a loss for CW and the community in most ways. It's hard to put a finger on exactly what your role has been here, some mysterious admixture of wise elder statesman, mentor, technical and sometimes non-technical advisor, voice of reason, unofficial company rep who gets to be a bit more forthright and off-the-cuff than an official one might, defender of clear writing and civil discourse... but anyway from my perspective it's been a good thing having you around and a good time for both the company and for us forumdwelling weirdos that appreciate this place (and don't quite understand the unbelievable bashing it gets in other forums), and I very much appreciate all your efforts and contributions.
On the other hand I'm excited for you - how many people get to say 'Hey, end of one interesting chapter, beginning of another! Cool!' at an age when many are retiring to the golf course (not that there's anything wrong with that!)? I'm in the middle of something similar myself, two decades or so behind you, and while the uncertainty can be a bit nerve-wracking the sense of possibility waiting to be explored is also exhilerating. So, enjoy!
I do hope you'll still pop your head in once in a while to check up on us, I'll personally miss your honesty and erudition on a more regular basis but I'm also curious to see what you get up to next!