Loft gives you an idea of how far and how high the ball will go. Drivers are the least-lofted clubs (not counting putters), while wedges are the most-lofted. The more loft a club has, the higher the trajectory on which the golf ball will travel.
Driver lofts for most players run between 9 and 12.5 degrees. Clubs increase in loft through the set until reaching the lob wedge, which is usually lofted from 60 to 64 degrees.
Also see:
FAQ: Are there industry-wide standards for the lofts of golf clubs?

