There's a bunch of stuff in the comments, everything from the old print '';var_dump();print '';
A list of wireframing tools, from free to expensive:
For reference: the Wikipedia page for Tetrachromat.
FWIW, Warner Bros. Records uses Drupal very heavily for its artist sites.
Check this out post, for example, on WBR's VP of Technology Ethan Kaplan's blog: http://blackrimglasses.com/archives/2007/07/26/wbr/
(Mind you, it appears that ecommerce may be handled outside of Drupal--whether that's due to some a lack in Drupal or some WBR-specific reason (e.g. legacy system), you'd have to ask check w/Ethan).
To save some time and to keep Google from having to pay loads of nickels to Mozilla as I look up various topics for interview-prep:
(GoF pattern examples: Adapter/Wrapper and Strategy patterns).
MySQL for Grown-ups:
For various reasons, MySQL has been undergoing a lot of development outside of MySQL AB (now part of Sun). This is meant to list some of the more important players/packages/etc.
Read the comments too.
Chairman of the Bored.