I love Wild Oats! It is a full service grocery store with a lot of healthy products. Recently, they've decided to eliminate all products with transfats! This is a great step that others should imitate! They have a lot of organic fruits and veggies and a great bulk foods section. I love the bulk spices, so you can try just a pinch before committing to a whole bottle of something you're not sure you like.
The prepared foods area is great. They have everything from sushi to pizza to soup to tempeh salad. They have both vegetarian and meat-filled options, so it should be able to please everyone at your picnic! I recommend the roasted vegetable salad (when they have it) and their desserts!
They also have a great community room available for your next meeting!