Wow. All this WinMo love is making me tear up!
I'm still a WinMo fanboy, mostly because at the end of the day, I get more done with it. I'm still a file-based guy, and I feel like no one else sees how the newer mobile OSes are really a step backwards in terms of computing. Back in 70's and 80's, when computers weighed 40 lbs and were powered by coal, we ran a program, and worked with our files inside of that program. Then, as graphical user interfaces became popular, computing shifted to where we worked on our files, and the OS figured out what program was needed to manipulate those files.
Then iOS shows up, and "apps" took us right back to 1979: you want to open a note, an ebook, or a spreadsheet? Find whatever "app" created/owns it, open the app, and the app will access the file, maipulate it, and even handle moving it off the device, because the sandbox won't let any other app access it. Sheesh! It's like owning a VIC-20 all over again!
WinMo is certainly flawed in many, many ways, but it still stands as the best implementation of a PC-like experience on a handheld device. It's totally autonomous- no outside computer is needed to "kickstart" it, no cloud server needed to "activate" it- you take it out of the box, and it just works, like any PC would.
Android is the closest modern OS to the WinMo ideal of autonomous computing, but it has awkward file management (which is still better than the non-existent file management of iOS and WP7!)
In my household, we have iOs devices, Androids, WP7s and WinMos, and I still use the WinMos 95% of the time (mostly my HD2, but occasionally my Treo Pro and Sony X1, all in sync via Dropbox.) I love the WP7 UI, but the OS is far too walled in and dependent on MS services (take away Skydrive and Bing and the thing is a dumbphone with a big screen.)