I have had pretty good luck with Annie's Annuals...I purchase zone appropriate plants and my favorite so far has been Trachelium caeruleum 'Hamer Pandora'.
I also agree about topography and differences in my own yard. Cold air pools in low places. My back yard is at least 8' lower than the front, so the bananas, cannas and ginger (I DO love tropical plants) are in the front.
