Please.

I've been using the same password for nearly everything for over a decade, and never a problem has arisen. 

Scary. Has anybody asked themselves "Do we really need to spend so much time and money on all these sensors to make our computers slightly more convenient?"It wouldn't be worth the money to me... but the opportunities for abuse are huge.

Think of the possibilities for rejection (Woody Allen comes to mind) and logon problems (if one gets injured and need plastic surgery or grows a beard):

If it detects a human presence I doubt it would work for me.

Forgot to shave this morning? No work for you today.

The real-world translation, based on my experience practicing medicine:

Once this technology matures, you'll be required to obtain a Federal Face-Verification Code from the Bureau of Facial Recognition, Division of Passport Control, US Department of State, in order to use a computer once you've registered with, and been granted a license to purchase one by, the Personal Computing Division, Computer Security Administration, Department of Homeland Security.

Your DHS Application for Authorization to Acquire and Use a Personal Computing Device will require a complete list of all intended uses, end-user applications (programs) applied for, cloud storage provider to be used, a fingerprint card verified by your state Department of Public Safety (properly notarized), permission to conduct an FBI background check and access your cloud computing account, and a CRS (Certified Retinal Scan) obtained from your local Passport Office.  Once you've satisfied those requirements and paid all applicable fees, you'll be issued a Personal Homeland Security Random Code Generator for your 3-level secure login, and you'll then be permitted to present your license to a designated Homeland Security Certified Retailer to purchase a computer (with Windows 8!).

Once it's been delivered to your home by a Federally-Certified Personal Computing Device Delivery Service and set up by a Federally-Certified Home Computer Installation Specialist, you'll be required to activate your OS by calling a dedicated line at the Personal Computer Activation Service, Microsoft Division, Federal Bureau of Investigation, US Department of Justice, and following the prompts, enter your 25-digit alphanumeric OSIN (Operating System Identification Number), 10-digit Device MAC (Media Access Control Number) and 16-digit Federal Face-Verification Code.  If you've made no mistakes, you'll be prompted to get in front of the computer so it can see you and to login to a secure Homeland Security website using an 8-digit access code provided by the AVR (Automated Voice Response) system.  A Federal Active-X Control will scan your system & if your face is recognized (the retinal scan is only needed for activities requiring a Security Clearance of Secret or higher) and everything matches with Homeland Security's SDACU (Secure Database of Authorized Computers and Users), it will activate your OS & you're just good to go.

Of course, the above assumes you've already registered your voice with the Voice Recognition Verification Division, U.S. Bureau Immigration and Customs Enforcement, Department of Homeland Security, and paid the applicable registration fee.  Otherwise the Computer Activation Service won't recognize your voice and will just hang up on you.

If you plan to use certain software applications with potential security implications (these will be identified in the course of your Application for Authorization to Acquire and Use a Personal Computing Device), you'll need to obtain a Registration Number from the Division of Potentially Dangerous Software, Bureau of Alcohol, Tobacco and Firearms, U.S. Department of the Treasury, in order to use them.  Registration must be renewed every two years; initial and renewal fees apply.

Oh, and if your computer is a notebook or other mobile device, and you plan to travel with it, you'll also need to apply to the Personal Mobile Computing Division, Transportation Security Administration, Department of Homeland Security, and pay for a Computing Device Mobility Authorization Card verifying that the notebook is certified safe for transport via commercial carrier, to avoid needless delays at airports and other TSA screening facilities, and to free up TSA screeners for more bra-checks & crotch-fondling.

Windows 8 is gonna be awesome!

So in Windows 9 I take it there's going to be snarky comments about grooming coming from the computer.

Probably not. It will just automatically contact a Microsoft-approved plastic surgeon to come to your house that night while you are asleep.

Or works like an alcohol lock on a car. 

Win 8 looks at you goes eeeeeek and shuts down.

Remember, if you have a camera in the computer and get infected, some hacker in another country could use it to watch you.  If M$ thinks I'm going to put one on my home desktop so my PC will know I am me when I'm the only person that ever uses it, they can think again.

The sane-user equivalent is:  Amish walks in to his home office, powers up the PC and  {opens the blinds | brushes his teeth | cleans the cat's litter box | fires up the coffee machine}.  By the time he sits down, his PC is powered up and waiting for him to log in.  Works with XP too.

Other issues with the M$ scenario above include the machine powering up then a cat wanders by, and powering off then the human goes to take a break.  Or remaining powered on for longer than needed if the human sets a long timeout to avoid the "break" problem above and then leaves without turning it off manually.  I can turn my PC off all by myself, thank you very much.

So M$ will code this silliness, charge more for Win-8 because of all its extra features, and wonder why so many of us stick with XP, Win-7, etc.

You suggesting I'm not sane, LC? 

I like Daiwa's "Parable of the lost Shangri-Lala". He thinks as cynically as I. Thanks for that comment Daiwa - it was great!

Aw great, now my computer's going to point out that I have a large nose every time it boots. 

Still, at this rate my computer will turn into GLaDOS by the time Windows 12 rolls out.... wait. I just counted them, Windows 7 is the ninth at least.

Windows 7 has only been out for 2 or 3 years and they're making another OS? geez... what did they find wrong this time or what did they bork up now in windows 7