Since this is an anime forum i'm curious what tastes people here have in regards to music in anime. I think that's an aspect of the medium that gets overlooked, so feel free to post any musical pieces that stand out to you. If you can, I would also like to encourage anyone to express why you think the music suits the anime or why it doesn't.
My first pick is a personal favorite of mine, the opening theme for Ergo Proxy "Kiri" by Monoral. I really like this song because it does an effective job of setting the tone for the series. With the lyrics alluding to the dynamic the main characters develop with each other over the course of the series. It's a good song on its own, but it works well as something of an opening prologue for the show too. It's also sung in english, which helps make it pretty memorable.