Carbohydrates are absorbed by the body at varying rates.  The glycemic index (GI) measures how much a fixed amount of carbohydrates from a food raise glucose level.  Thus high GI carbohydrates are digested quickly and so tend to lead to hunger, whereas low GI carbohydrates tend to suppress hunger.  GI does not take into account the caloric density and other factors influencing a food's glycemic effect.  A better measure is glycemic load, which refers to how much a standard serving raises glucose levels.  When I find values of the glycemic load, I'll post them instead.

Current recommendations are that at least 1/3 of your carbohydrates should have a GI that is 55 or below (Dr. Wolever, coauthor of The Glucose Revolution: The Authoritative Guide to the Glycemic Index in a Bottom Line, Jan. 15, 2001).

• FRUITS  There is a wide range.
       Two rough rules are: more tropical is higher and sweeter is higher.
       From low to high:
    20  cherry
    25  grapefruit, plum
    30  peach
    40  apple, pear, plum
    45  grape, orange
    50  kiwi
    55  apricot, banana, mango
    60  papaya
    65  cantaloupe, pineapple, raisin
    75  watermelon
  100  date
  
• GRAINS   Generally, less processed means lower GI.  Also, whole grains appear better than refined ones with similar GIs (SN 5/18/02 p.308).
  Barley ranges from 25 (pearled) to 65 (rolled).
  Breads range from 40 (punpernickel) to 95 (French) and are mostly in the 60s.
  Cereals have a wide range.  Most of those not thought of as sweet are from the 60s to the 80s.
               At the low end, All-Bran is 40.  At the high end, Rice Chex is 90.
  Pastas (including whole grain) range from around 35 for al dentes to 50 for well cooked.
  Rice (white, brown, wild) is about 55, depending on variety and cooking.  Stickiness indicates high GI.
  Rye (whole) is 35.
  Wheat (whole) is 40.
   
• VEGETABLES   There is a wide range.
  Carrot is 70.
  Corn is 55.
  Legumes are in 30s and 40s, but Soy is only 20.  Canning often adds 5-10 to values.
  Parsnip is an amazing 95!
  Potatoes are 85/60 for boiled red/white and 95/85 for baked red/white.
  Pumpkin is 75.
  Rutabaga is 70.
  Sweet potato is 55.
   
• MISCELLANEOUS
  Chocolates are around 50.
  Ice creams are around 60.
  Milks are around 30, depending on fat percentage (skim is highest; whole is lowest).
  Peanut is 15.  (The only "nut" I found.)
  Yogurt (plain) is about 15.