I've outlined some of the design decisions I made when designing Sands, including why some links are black, the use of a em-relative layout, and why I think they are more usable, in a post on Drupal's forums: Any theme with high usability?
Samat Jain is co-founder of a web services company based in his hometown, Rhombic Networks, LLC, where he currently serves as CTO, system administrator, and programmer.
If you like his site, please leave a comment on your favorite posting, or contact Samat and let him know!