This appears to be the best DVD of La Sonnambula available. Amina (Eglise Gutierrez) is amazing, so this one will be on my to-buy list hoping the price will come down on used copies someday (it is a more recent production):
Meanwhile, I purchased this one for a very reasonable price ($1.75 USD used) and Amina (Eva Mei) sings beautifully on it, but the staging is quirky at best:
It is also available for more money in a newer release:
But as this is my first La Sonnambula, it will do quite nicely to get acquainted with this opera.