Vegetables:

Alfalfa sprouts
Basil
Beet greens (tops) *
Bok choy
Broccoli (mostly leaves/stems) *
Brussels sprouts
Cabbage leaves (outer)
Carrot *
Carrot tops *
Celery
Cilantro
Clover
Clover sprouts
Collard greens*
Dandelion greens and flowers (no pesticides) *
Endive *
Escarole
Green peppers
Kale (!) *
Mint
Mustard greens *
Parsley *
Pea pods (the flat, edible kind) *
Peppermint leaves
Raddichio
Radish tops
Radish sprouts
Raspberry leaves
Romaine lettuce (no iceberg or light colored leaves) *
Spinach (!) *
Swiss chard
Watercress *

(!) Use sparingly. High in oxalates or goitrogens and may be toxic in accumulated quantities over a period of time

Fruits (as treats only):

Apple
Blueberries
Cactus fruit
Melon
Mango
Orange (the peel, too!)
Papaya
Peach
Pear
Pineapple
Plums
Persimmon
Raspberries
Strawberries
Tomato
Banana (Can be "addicting"; use only occassionally)
Dried fruits can be used
Raisins (Watch out for sugar!)
Craisins (sun-dried cranberries... watch out for sugar!)
Grapes

Things you shouldn't feed:

Any grains (many suggest this; however, it is not good for them)
Chocolate (poisonous to rabbits)
Cookies, crackers, cereals, bread, or pasta
Yogurt drops (Almost pure sugar--can kill your rabbit!)
Other "human treats"
Salty or sugary snacks
Nuts
Corn
Onions (can be fatal!)

Salt or Mineral Block:

This is not necessary for a house rabbit on the diet described here and on the diet page

Night Droppings:

Cecotropes, a kind of dropping, appear 4-6 hours after eating. They are necessary for rabbit nutrition. Cecotropes are softer, greener, and have a stronger odor than normal waste droppings. Cecotropes are very nutritious. Rabbits know when these droppings are being produced and will eat them on their own. A rabbit with a low-fiber diet or a high-starch diet may lead to chronic and persistent cecotropes which are too soft and liquidy to be eaten. These are left in little puddles with normal waste stools.

Water:

Water should be fresh, and the crock/bottle should be cleaned often to prevent bacteria from growing. Do not use medications or vitamins in the water, because your pet may not drink if the taste or color is altered.

Pinecones?

Pinecones make wonderful snacks/toys for rabbits, but you must prepare them properly first. Take a pinecone and wash it thoroughly to remove dirt, insects, and sap. Dry off the pinecone. Put it in the oven and bake it for one hour at 200 degrees.

The truth about store-bought snacks:

Treats for rabbits which are bought at the store usually aren't very safe. They contain ingredients which aren't good for rabbits. Save your money and buy your rabbits timothy hay and vegetables... these you can be sure are good treats!