It's the most absurd thing I've ever watched, it has an interesting story, but dear Satan the fan service is just too much.
Go watch it if you haven't already, besides all the boobage and sexual innuendos it can have some decent humor and story to it. If you've heard of Sekirei, this is like twice as provocative as that.
-
Complaining about fan service in Highschool DxD is like complaining about nudity in porn. The entire -blam!-ing point of it is fan service.