I think long hair is generally prettier and looks better on most girls.  That's just my opinion, though!

Can't wait for mine to grow long, long, long, especially as I have just heard today that I am going to be a bridesmaid at my best friends' wedding! :)  So excited!!

• looks beautiful
  
• takes less work with styling etc.
• can do more things with it
• makes you look special

• takes far too long to dry
• takes a long time to get there
• can't damage it (i.e dye, straighteners) as the damage takes so long to grow out
• if left down it gets tangled quickly and gets in the way

Pros:

• Looks great
• Easier to style
• Prevents boredom
• More options
• Less washing

Cons:

• Can't just change the colour whenever
• Can't straighten or heat-style every day
• Every little thing you do comes back to haunt you six months down the line
• Can look crap in winter
• Harder to grow out a fringe(bangs)

Well all the pros and cons mentioned above...PLUS:

Pros:

• Cheap! Don't need styling products, save on electricity from heat applicances etc.
• Great for lazy ppl....just put hair up and go!
• Enables you stand out from a crowd
• Gives you extra flair when dancing

Cons:

• You have to think about hair consequences (ie...if I do this, will it hurt my hair?). Can be a little bit stressful
• The weight can give you headaches/neckaches.

Pros of long hair for me:

• the different colors from tips to root and natural highlights are more visible giving hair more definition
• The waves in my hair are more visible and pronounced
• It is meditative and relaxing to comb it, wash it, and care for it

Pros of short hair - (I thought I'd do this instead of cons of long hair just because I've had short hair recently)

• great for sports or outdoor activity - don't need to worry about freezing weather when skiing, or salt, or wind, or....
• easy to wash and care for
• can be very cute depending on the style

Pros:

• Very versatile with unlimited styling options
• Classic feminine look provided its in great condition
• Can be worn up to simulate short hair
• Only ever an hour away from any short style if you have the desire to cut it off

Cons

• Takes enormous amount of time to wash and dry
• Can't wash and go in ten minutes
• Windy days
• Takes years to grow it long in the first place!!

Pros:

• Feels great on bare skin
• Can be used as a blanket when left down
• Hides "love handles" and other physical imperfections 
• Can be left in braids for days at a time

Cons:

• Must be completely contained when riding top-down in a convertible (unless of course you WANT damage)
• Takes forever to dry
• Can't (in most cases) get a professional trim without the stylist hacking off 6 inches or more
• One must learn to live with his/her natural hair texture, as regular curling/straightening will NOT fly

Here are my additions...Pros:

• Sock curling
• The combing process is very meditative
• Braiding, bunning, hair toys, comb-collecting...
• more dates

Cons:

• Can't headbang
• Takes so much patience
• There aren't enough cons

Cons:
-gets caught on bookbags/jackets of people walking past you when you are sitting in class
-again: takes forever to dry
-contrary to what most have said, I find long hair much harder to style than shorter hair
-very heavy (limits styling options, can lead to neck/headaches)
-impossible to leave down at work (I'm a stock clerk)

Pros:
-looks better
-long hair usually = attention (which could be bad I guess)
-warmer (ditto on the "blanket" thing).  Gotta love warm arms/nips/back on a cold day.
-makes a great Cousin It costume

And speaking of the long mop, I'm going to hop in the shower for a wash and deep condition.  Woot.

Pros:

- Feels lush and soft.

- Has a definite exotic appeal that does draw attention.

- Is sexy (on both men and women).

- Feels like silk on bare skin.

- Younger looking.

- Blanket Head: keeps your head warm in the winter.

- Helmet head: hair by itself is natural protection for your head, neck, and brain.

- Cool accessories.

- Many, many styling options that are easy to do.

- The understated elegance of a simple ponytail, thick braid, or french twist.

- Patience is rewarded - those with naturally long hair do not have to pay $500 to $4500 for extensions.  And I do not require those mostly hideous fake hair pieces you see on sale in stores and on QVC.

- Few things are as pleasurable as someone gently combing your long hair.

- The Sampson effect: this has to do with confidence that Vicky mentioned rather than strength.

Cons:

- Splits ends and wear and tear, the dry winter fuzz phase.

- Takes a long time to dry.

- Must avoid most trim-happy hair stylists  :-[

- Blanket head: hot in the summer.

- Takes great patience to grow and the ability to avoid many passing style fads.

- Long strands of shed hair can stop up your vacuum cleaner.  :-[

- The danger of being scalped (in rare circomestances, there are cases where women with very long hair have been scalped in accidents involving heavy machinery and even an amusement park ride.)  So boys and girls, if you have really long hair, be mindful of safety in your environment.