I like them all! Will you be doing FMQ or using a walking foot? I agree with the one that said an overall pattern would be great on #1,2,4. For the circles...not sure what I'd do. Maybe spirals in the circles and some smaller stippling or other to fill in the background. You might want to do a Google search on circle quilts (click images at top first). Maybe you'll see some completed ones to give you ideas.