I really enjoy database design and the whole concept of managing data semantically and all the logic that comes with it.
My knowledge level when it comes to databases is
http://www.pui.ch/phred/archives/2005/04/tags-database-schemas.html
http://blogs.msdn.com/pathelland/archive/2007/07/23/normalization-is-for-sissies.aspx
http://www.25hoursaday.com/weblog/2007/08/03/WhenNotToNormalizeYourSQLDatabase.aspx
http://itc.conversationsnetwork.org/shows/detail571.html
http://www.scribd.com/doc/2592098/DVPmysqlucFederation-at-Flickr-Doing-Billions-of-Queries-Per-Day
http://highscalability.com/flickr-architecture
http://highscalability.com/ebay-architecture
http://www.addsimplicity.com/downloads/eBaySDForum2006-11-29.pdf
http://blog.maxindelicato.com/2008/12/scalability-strategies-primer-database-sharding.html
http://blog.maxindelicato.com/2008/12/the-ihsdf-theorem-a-proposed-theorem-for-the-tradeoffs-in-horizontally-scalable-systems.html
http://www.iamcal.com/talks/
http://natishalom.typepad.com/nati_shaloms_blog/2009/04/writing-your-own-scalable-twitter.html
http://www.mysqlperformanceblog.com/
http://www.cecs.uci.edu/~papers/ipdps07/pdfs/SMTPS-201-paper-1.pdf
http://video.google.com/videoplay?docid=7278544055668715642
http://www.niallkennedy.com/blog/uploads/flickr_php.pdf