This new theme framework is getting some nice reviews: The Roots WordPress Theme by Ben Word.
From a review of the theme at Sitepoint.com:
To my thinking, Roots is a great example of the kind of features you should be looking for if you’re seeking out a framework. It’s up to date with today’s best development advice, it’s based on tried and tested projects that many developers will already be familiar with, and it’s been designed with speed and ease in mind—perfect for those of us who like to make it out of the office on time while still doing a great job. There’s a growing collection of documentation, and a glance at the project’s GitHub repository shows frequent updates to both the code and the manuals.
Data Enhanced 