Gregor Kiczales, Professor at the University of British Columbia, talks at Google about Aspect Oriented Programming. The video is very interesting and highlights a lot of advantages in using AOP. He demonstrates how you would be able to implement the Observer pattern without having to directly touch the involved objects. I actually have to try it out. Moreover he talks about how you could enforce architecture in your project or implement logging. I actually wanted to implement logging with Spring AOP when working on my thesis project, however unfortunately due to time constraints I wasn't able to try it out fully.
If this sounds interesting to you, just watch the video.
57 min 18 sec