WordPress upgrade blank pages
Seems many have encountered strange problems with blank screens upgrading to 2.5.1 and beyond. I had similar problems and finally gave up on 2.5.1 due to a lack of time. 2.6.1 somehow magically solved my problems with one blog, but created the dreaded blank screen when trying to view blog entries for another.
http://www.colinmcnulty.com/blog/2008/07/08/solution-to-wordpress-blank-screen-of-death/
seemed on the right track, yet my admin screens worked fine, it was the blog itself that was invisible. Out of frustration, I tried changing from the Default (Kubrick) theme to the “Classic” theme, and my blog was back! Switching back to the Kubrick theme worked fine also. Something must have been corrupted in the database relative to the theme entries.