I wouldnt do an Amazon in a 11 gallon tank as it will get way to big. I do like them though. There are really so many different plant types and personal preference varies.
I would go to
www.plantgeek.com and click on the plant guide. From there you narrow your search by lighting type.
Crypt. Walkerii Lutea is on of my favorite for smaller tanks with low-mid light as it has the looks of a large plant in a small frame. It also grows slowly and require little maintenance. Finding it locally may be tough depending on your local stores.
Vals,other crypts, java fern and moss,stem plants such as Wisteria and Rotala are also great. So many more to list and all unique in their own way. Have fun and post some pics when you get some!