I've gone through the Dorothy Sayers mysteries three times, read every single Agatha Christie in my county library system, and completed the Josephine Tey canon this past year by obtaining To Love and Be Wise via interlibrary loan. What shall I read? Like Cookie Monster, I wandered panicked among the library bookshelves muttering "Me want mysteries," and lighted once again upon Ellis Peters. I'd tried the Brother Cadfael mysteries twice before, and did not find them quite as perfect as Sayers and Christie nor as fetching as Tey. Nonetheless, I am now on a medieval kick and Cadfael fits the bill.
I just finished Monk's Hood and very much enjoyed the vividly described abbey and town.
Here is a helpful and attractive set of webpages by a Brother Cadfael fan, including a bibliography of the mysteries in order.