Updated documents as of August 2015.
Grasp Taxonomy Comparison Sheet (pdf, 9.4 mb)
Paper in IEEE Transactions on Human-Machine Systems, 2015 (pdf, 1.3 mb)
Taxonomy (pdf, 1.7 mb)
Property Table (pdf, 1.7 mb)
3D models of the grasps (rar, 12.7 mb)
For reference, the old taxonomy documents can be found here.