One thing I recommend to anyone who asks me about what they should grow in their first vegetable garden is that they first think about what it is that they like to eat. And people tell me, almost 100% of the time, that they really want to grow their own lettuce for fresh, healthful salads.
I don't blame them. There is so much to lettuce besides iceberg and Romaine. What about sweet, tender 'Buttercrunch' or beautiful 'Lollo Rossa'? "Deer Tongue,' 'Sanguine Ameliore,' 'Mascara,' and 'Oak Leaf' -- how could you not fall in love with lettuce, when it offers so much variety and beauty, not to mention flavor?
There are actually 5 main types of lettuce: crisphead, cos (Romaine), butterhead, Batavian, and looseleaf. The first four are essentially "head lettuces," forming a central rosette of leaves that grows in on itself. You harvest head lettuces by either cutting off the entire head, or by taking the outer leaves as you need them. The last type, looseleaf, also known as "cut-and-come-again" lettuce, is the one I most often recommend.