I too like to have big open plain areas for handquilting. Usually in pieced areas I tend to quilt 1/4" from the seam and save the open squares for the "fancy" designs. Samplers work really well for that because you usually get some nice open spaces along with pieced spaces to do a little of both straight line and curved quilting.
So just about any pattern works well for handquilting if you have some open blocks or open area to quilt with no seams. I have never hand pieced but I am working a hand applique project right now.
Edited to add, plain fabric that is solid or reads almost solid like a marble or blender show off the quilting the most. Printed fabric your stitches are often not as visible.
Edited again to add link to pictures of my current HQ WIP. I have been working on this for almost 3 years now.
http://www.quiltingboard.com/t-47093-1.htm