Oh yes, a few Echinacea are a must in any sunny garden. I would suggest starting with three or so varieties/colours.

As for the Big Sky series, I don't think they are a bust, but some people have had bad experiences, while others have had good/acceptable experiences. The key in all cases, is to plant healthy, mature plants in late spring or early summer.

I would not recommend 'Double Decker'. A variety like 'Pink Double Delight' is 10X better.

And yes, 'Kim Knee High' has been great for most. It is somewhat shorter, and has excellent branching, so puts on quite a show.

Good ol' seed strains like 'Magnus', 'Ruby Star' and 'White Swan' are great plants to begin with. They'll self-sow if you let them.

I loved 'Tiki Torch' this year (planted last year). I posted pictures earlier this summer.