Planet13 - 4:52 am on Feb 2, 2012 (gmt 0)
Just my two cents here...
I had a somewhat similar situation when i accidentally noindexed my home page back in late February of 2011. Some of my pages behaved the way you described.
So before going the reconsideration route, I really recommend having someone out there (not me) take a look at your site for technical errors.