This one is a no-brainer for me. Mark Bittman's NY Times'article on 101 Simple Salads posted during the summer has become a mainstay of our dining repertoire. Here's the link. Bookmark, refer to it often, and enjoy!
p.s. Bittman has done similar lists for suppers, picnics and appetizers. I can't find a link for the appetizers. I seem to have only a hard copy of the article. I'll keep looking and update.