If you didn't know any better, you might think that all of the good ideas about software development come from architects -- the kind that make buildings rather than bits. "A Pattern Language" is a classic book by Christopher Alexander on architecture and urban planning. It went on to inspire the Gang of Four design patterns book, the first wiki by Ward Cunningham, and even the Agile development methodology.
"Design Thinking" by Peter Rowe is another example of a book written for architects that has gone on to inspire software developers as well. While you'll find similarities to the Agile methodology you're familiar with, there are some interesting differences in Design Thinking, especially around taking a solution-focused approach rather than a problem-focused one.
In this talk, Scott Davis (Principal Engineer, ThoughtWorks) offers a hands-on, user-centric flow of understanding, exploring, and materializing to arrive at solutions to a problem. Companies as diverse as Apple, IBM, and SAP successfully use this creative way of problem solving -- perhaps you can as well.