I have developed a few great sites using original WP Twentyten theme and redesigned using a child theme. It works perfect and are very easy to update because i am using functions.php and and very small adjustments in the header.php. Is there actually any reason to use/ create a "full" theme if me is satisfied with the standard features in WP?
This is how one of them looks. http://golfami.onewebdesign.se
Happy for some thought from some pro´s.