Genghis has very well described the forces at play, but just to emphasise - most of the energy required to reach orbit needs to be applied to accelerate an object AROUND the earth, not AWAY from it.
A SUBORBITAL spaceflight, as performed by the early Mercury missions, merely flung the spacecraft (moreorless) straight up, and unless you go really really far away from earth in one go, this will not be good enough - you will eventually fall back to earth as gravity still acts.
For ORBITAL sapceflight, the force provided by gravity must equal that required for centripetal acceleration of an obejct in orbit around the earth. This requires fairly massive speeds, hence this is where the bulk of the energy goes.
This is why, after they get a good amount of seperation from the ground, you see spacecraft turning to accelerate horizontally.
Hope that makes sense!