Some of my fave patio furniture pieces are from Russel Woodard's "Sculptura" Line. Find them on eBay or check out www.JetSetModern.com. I found the settee and 4 chairs for sale. Yum!
Harry Bertoia's Diamond Chair are more patio must haves. eBay is a great source for vintage Bertoia but if vintage is not your thing, Charlotte's DWR has these available. They look great inside as well. Very swanky.
Can't blog about Mid-Century Modern patio's without mentioning Salterini's tangerine slice chairs. I missed a set on Craigslist! I am not sure if they are comfortable but I think they are so cool looking!