What role(s) do perennials play in your garden?

I am curious about what role perennials (annual too I suppose) play in other people's gardens, because I am not sure I have come to the right balance of shrubs, trees and perennials. I have had beds dominated by perennials that were a lot of work to maintain and looked bad for half of the year. I have had beds that were dominated by shrubs but honestly I found them a tad boring. What has worked for you?

As I think about it...maybe my biggest issue is my lack of hardscape elements...hmmm.

- Brent