Hi John,
I've been using S3 with ES since Beta but it got fixed 2-3 versions before V1.0 was released. Make sure the your Access Key and Secret Key is working, you can test it our using Firefox addon Amazon S3 Organizer just to make sure its working. Under Bucket Path just enter the Bucket Name you created, the subfolders will be autocreated by ES. For example, if you created an S3 Bucketname "easysocial" - without quote, just enter easysocial in the bucket path field. In my setup, only Bucket Path in Amazon S3 tab is all I set.
In v1.1.0, something is wrong though, I already submitted an issue about it. After all your photos gets uploaded to S3, the images in your stream will not show up. The image paths were not updated to S3 after the upload.
Hope that helps!