What should I expect from a Belgian triple (tripel)? I know from this question that doubles and triples are stronger than the "single" version. And from what I've seen, Belgian triple are often closer to be blond and golden while doubles are often darker. 

My question though is what should I expect from a triple? What are it's defining characteristics (meaning that I can recognize one when I drink it, or recognize an off-style one)?
I expect a high alcohol beer, with a lot of complex flavors.  One that the alcohol content will "sneak" up on you because it isn't very obvious in the taste.  

Quoting from the Beer Judge Criteria:


  Aroma: Complex with moderate to significant spiciness, moderate
  fruity esters and low alcohol and hop aromas. Generous spicy, peppery,
  sometimes clove-like phenols. Esters are often reminiscent of citrus
  fruits such as oranges, but may sometimes have a slight banana
  character. A low yet distinctive spicy, floral, sometimes perfumy hop
  character is usually found. Alcohols are soft, spicy and low in
  intensity. No hot alcohol or solventy aromas. The malt character is
  light. No diacetyl.
  
  Appearance: Deep yellow to deep gold in color. Good clarity.
  Effervescent. Long-lasting, creamy, rocky, white head resulting in
  characteristic “Belgian lace” on the glass as it fades.
  
  Flavor: Marriage of spicy, fruity and alcohol flavors supported by a
  soft malt character. Low to moderate phenols are peppery in character.
  Esters are reminiscent of citrus fruit such as orange or sometimes
  lemon. A low to moderate spicy hop character is usually found.
  Alcohols are soft, spicy, often a bit sweet and low in intensity.
  Bitterness is typically medium to high from a combination of hop
  bitterness and yeast-produced phenolics. Substantial carbonation and
  bitterness lends a dry finish with a moderately bitter aftertaste. No
  diacetyl.
  
  Mouthfeel: Medium-light to medium body, although lighter than the
  substantial gravity would suggest (thanks to sugar and high
  carbonation). High alcohol content adds a pleasant creaminess but
  little to no obvious warming sensation. No hot alcohol or solventy
  character. Always effervescent. Never astringent.
  
  Overall Impression: Strongly resembles a Strong Golden Ale but
  slightly darker and somewhat fuller-bodied. Usually has a more rounded
  malt flavor but should not be sweet.
  
  Comments: High in alcohol but does not taste strongly of alcohol. The
  best examples are sneaky, not obvious. High carbonation and
  attenuation helps to bring out the many flavors and to increase the
  perception of a dry finish. Most Trappist versions have at least 30
  IBUs and are very dry. Traditionally bottle-conditioned (“refermented
  in the bottle”).
  
  History: Originally popularized by the Trappist monastery at
  Westmalle.
  
  Ingredients: The light color and relatively light body for a beer of
  this strength are the result of using Pilsner malt and up to 20% white
  sugar. Noble hops or Styrian Goldings are commonly used. Belgian yeast
  strains are used – those that produce fruity esters, spicy phenolics
  and higher alcohols – often aided by slightly warmer fermentation
  temperatures. Spice additions are generally not traditional, and if
  used, should not be recognizable as such. Fairly soft water.