I got the same thing as Martinbuster, I just wish the stupid thing would go away. All of my google stuff is connected to my gmail address so for now I have been skipping the wizard. It is still annoying that I can't just log in and be done with it. Strangly no other services are popping up with this for me.
I have no idea why they can't write a short script to take all Adsense accounts which aren't part of a Google Account and automatically create a Google Account with exactly the same login details as the Adsense Account.
I didn't read this full thread, but I have to tell. Google asked about this change months ago. At that time, I did it and it worked. It was first the Adwords account, later they informed me to change the Adsense account and I did it as well. All worked fine... at that time.