Emergencies:
You should have three months of income in fairly liquid money.  (Remember that "liquid" means that you can get your hands on it quickly without eating a penalty.) 

The first thing that young people usually say about this one is, "Why?  I'm young and healthy.  Nothing's going to happen!"  But, what if you're in a car accident and can't work?  What if you lose your job?  Things are tough out there and it may take you awhile to find a new one.  I've heard some people say that, if you're in an impacted and unstable field (like IT), you should have NINE months of income set aside for an emergency.

The second thing people say is, "But, I'm just barely getting by.  How on earth am I supposed to save this much money?"  Check out my Pay Yourself First and Give It Up to Get Rich articles.

Your First House or Condo:
This will be your most important and most lucrative investment...  And you'll need that down payment!  Don't buy the new car.  Save that money for the down payment.  Don't spend a lot on your wedding rings and wedding.  Save that money for the down payment.  Don't spend a lot on lavish vacations (you will have earned these more later).  Save that money for the down payment.

Your Retirement:
Did you read about the magic of compound interest?  When you are young is exactly the right time to plan your retirement!!  Plan correctly and, even if you make just an average income, you can retire early and extremely comfortably...  Maybe even rich!

College for Your Kids:
Once again, the magic of compound interest will come to your aid.  When that kid is born, start the savings account!  If you're at the right income level ($95,000 for a single, $150,000 for both, if you're married), you can start an Education IRA and put in up to $500 a year.  If you do $500 a year at 10% for 18 years, you can have $22,799.59...  Nothing shabby about that.