Have you considered going to your local library and checking out some books on perennial gardening? When I started out I got lots of ideas (for free!) from checking out books in the gardening section at our local library. Many of the books had detailed plans for planting a garden like you're doing. I thought of daffodils (mine always bloom before my tulips), lily of the valley (usually blooms in May here), and giant purple Allium. I would strongly recommend some daylilies and stargazer lilies for summer blooming ideas. Good luck!

I second the allium. I'm very fond of the Schuberti, which reminds me of fireworks.

Mine has been in the ground 5 years, and while it doesn't spread, it does come back year after year.

I absolutely love oriental lilies. They do spread, and they scent the whole yard. Take a look at the white Casa Blanca. I can't say enough nice things about it.

And this year, I'm putting in many, many more crocus.