Don't forget to check out Tarptent's offerings. They are extremely lightweight, and pretty affordable too. I use the Contrail and put my pack under the "beak" vestibule.
Amen, I love tarptents also for several reasons: They are lightweight, affordable, pack very small for a tent, very versatile, extremely waterproof, and most have a vestibule that's great for keeping gear dry while it's pouring.