i've also been surprised that some of the most radical christian theology is coming out of the catholic church -- particularly in the areas of feminist and liberation theology.

i recommend she who is by elizabeth johnson and in memory of her by elisabeth schussler-fiorenza if you haven't read them yet. they're both pretty hardcore academic theology, but very very good. (i had thought s-f was protestant, but read something recently that suggested she's catholic, so i'm confused now. but she's pretty foundational in any case.)