Now, I am all motivated to use these templates sets after seeing Lisa's book again and visiting Heather's books for the first time. Thanks for sharing those links!
Robynne, you narrowed your choices down to two really lovely sets for a blended look. You are wise to learn from Cassie's tutorials, too. If you haven't already done so, now would be a good time to pick up Cassie's tutorial on using templates.
Getting Started With Templates. I think this tutorial would really help you get off to a good start using a template set like either Katie's or Anna's.