Do you follow your blogs through Google Reader?
If you answered yes, are you having trouble unsubscribing/deleting blogs from Reader?
Because I am - I try to unsubscribe, only to have the unwanted blog make its way back into my feed at some later point.
So far, I've tried to delete blogs by clicking the arrow next to the name in my list of blogs, and selecting "Unsubscribe." The blog reappeared some time later. I have also tried clicking on "manage subscriptions" and deleting blogs that way. Some still reappeared.
Edited to add a followup: Thank you, lovely readers! It appears that I needed to unfollow via the Blogger Dashboard. Fingers crossed!