Fotiman - 7:38 pm on May 23, 2013 (gmt 0)
That certainly is a valid HTML5 document, though personally I would still include the <html> tag. Note, the original question was regarding the DOCTYPE, and the <html> tag is not a part of the DOCTYPE. Also, the meta tag can be shortened in HTML5 as well.
Here's the ideal starting point, in my opinion.
<meta charset="utf-8" />
<!-- Put styles in the head, but make sure charset is 1st -->
<!-- Put scripts just before closing body tag -->