Cocktail reception: It's hip and modern, and it's also enjoyed a lot by guests. It may cost a lot less than a sit-down, but it can suffer from feeling a bit disorganized and hard to gain the attention of guests for cake cutting and toasts.
Picnic: Great for nature-loving couples, and easy to arrange catering can be done using your local favorite sandwich place. Since it's outdoors, there can be a risk of rain and some people might find this too informal for a wedding.
