Lately I have been focusing hard on the optimization of the design implementation process for Drupal sites. 'What should the designer take into account when designing for Drupal?' and 'Is this or that design (element) possible in Drupal?' were the key questions I was trying to get an answer to.
These are my tips to optimize your designs for Drupal, leading to a faster implementation.

I too agree the combined approach of using DS and Panels together. Alternative to using DS and Panels would be to use Omega Theme + Delta + DS + Context, which is slightly less flexible than DS + Panels, but it gives a lot of advantages too (e.g. 960gs for one).
I'd say, go for DS and Panels if you use Zen / Adaptive, etc, and drop Panels if you use Omega Theme :)