well, you don't have to connect the pc to your Microsoft account, on install you can just not give the credentials, and use a local account, just like in win 7. Dunno tough why it was eating so much processor power tough. The Metro email app can take ass much email accounts as you like just go to its settings and add account, works with gmail, and few others too. tough you probably want to install just smth like Thunderbird, there isn't much features in that metro email, just like every other metro app is useless for power user. So to get rid of it, just get classic shell, a customizable standard looking start menu. Besides Microsoft is killing hotmail, no one is using it anymore, and looks like they are merging it to skype.
And well you can use the same microsoft account on multiple computers, and then your settings will be automatically synced between the PC:s, like your wallpaper. And the sync for different elements can be turned of in the settings(metro app). Also the slide up "lockscreen" can be turned of so you don't have to swipe up every time.
There are few nice improvements on desktop side, Task Manager is really nice, file transferring is way better than it was in win 7, you don't need something like teracopy anymore. And it can mount disk image files to virtual drives without any 3rd party programs, no need to extract those .iso files anymore.
There are thing i don't like in win 8, like the on-screen keyboard, believe or not, it was better with windows 7 on a tablet. I have windows 8 on both my series 7 slate and my desktop PC.
The Hulk in me has calmed down. I got Classic Shell and it's been very helpful. It allows me to bypass the Start screen altogether, which I'll probably use. The fact that so many users need to use a this-party program to use the OS for the most basic of tasks should tell Microsoft someting.
The thing about the Microsoft account was that I already inserted my credentials instead of using a local account, and reverting isn't probably a 3-step process. I really have no need to sync different computers, I only use a gaming desktop with XP and a work+everything else laptop.
I've always used thunderbird, it works flawlessly, before that I used Windows Live Mail, which was maybe the best e-mail client ever until it just stopped syncing my account even after fresh re-installs. Thunderbird doesn't allow you to do things like delete an e-mail in your hotmail inbox after deleting it on Thunderbird, or I can mark something as spam, but I still get e-mails from that address. Basically it shows you your e-mail, but it doesn't let you control it. For this Windows Live Mail is better, and I was hoping to use it, although I don't think I'll use the Metro app.
Messenger doesn't let me add more accounts, the only option I have is to connect my Microsoft-and-hotmail account with my facebook account. I'll have to check more into that.
Haven't tried file transfer yet, but I like the new Task Manager. Another great loss was the desktop miniapps, I know most just used things like calendars and clocks, but the CPU Meter and Network Meter were lifesavers, if I hadn't installed them I'd never know when my CPU was 10 degrees away from shutting down my computer.
I think more than re-inventing the UI, its about Microsoft trying to stay relevant in a world where fewer and fewer people are buying PCs. Its a last ditch attempt to get some of the tablet users on board, and hopefully sustain Window's presence in home/personal use. Otherwise, Windows will be relegated to offices and for those who develop for phones and tablets or tasks that need serious horsepower, much like Linux is used mostly by enthusiasts and for research/development.
The thing though, is that an OS is only a small part of the equation nowadays, because of standards that enable small applications to work on different platforms and OSs. You don't need 10 different ways to run Twitter, or Facebook, because these apps are becoming OS agnostic. The world has changed, and for better or worse, they're more interested in devices that let them consume rather than produce.
The only approach left to sell the OS is to tie down the hardware with the software, but thats what MS has been doing for a while. The thing is, no one wants that hardware anymore.
I think Microsoft needs to think hard about this. They need a serious breakthrough, *both* in hardware *and* software.
Its like the slugger who's waiting to throw that one good punch to end the bout, but it may or may not happen.
I get the feeling this was used to appeal more to the common user (no depreciative meaning) who checks his/her e-mail, writes a facebook status about sushi, sends a message to a friend and looks at pictures of cats. It wasn't made for serious users who like to control their computers. That's a feeling I have a lot, it's that while in 7 I knew pretty much which processes were running, here it's like my desktop is a sandbox with lots of stuff going on in the background. Sometimes when I close a Metro app (which only seems to work with Alt+F4) it still runs on Task Manager. I really can't see someone who owns a fan controller ever using Windows 8 as it is.
I get the idea of having an OS that can run on anything, it makes sense. Simplicity appeals to most people, and something that fits more devices is simpler. But if it's done at the expense of productivity or usability, then it becomes a demand. If you're not improving anything by changing, then you're probably not changing for the better. Here's a really bad analogy: I used to play Magic: The Gathering nearly everyday. I read the Kamigawa block books about twice, and tried to make a deck that included characters and artifacts which were related on the story, which ended up a deck with lots of Legendaries and rares. It had a concept behind it. Of course my friend's rat deck, which had only a few rares and no concept (other than rats) demolished mine. It didn't have a story or an idea, but it was practical.
I don't understand the part of tying the OS. Most computers come bundled with Windows, but you can uninstall that OS and install another one, that's what I did. I thought Apple was the one tying its OS with hardware. I really hope MS understand that as cool-sounding as one-OS-fits-all sounds, if in the end a huge part of their customer base can barely adapt they need to change things. If the Metro UI was optional, or if you still had 7's Start Menu then people might volutarily adapt. There would be less people using Metro, but the ones that did liked it. Instead it forces us to adapt or go into the grey market of third-party apps. I don't know if something like a start menu could come included in a Service Pack, aren't they usually just small changes?
Windows 8 managed to shave second or two from it making the start up almost instant. 
