Pre Training Formula's are good as they allow stimulus of NO(Nitric Oxide) so that one can train harder and faster. L-Argine and L-Citruline are two vital amino acids that triggers Nitric Oxide production which in turn builds strong muscles and trims down fatty acids.
Some examples of good pre workout supplements are as follows:
Lower Priced: N2KTS has some great reviews and gives good energy and pumps
Jack3d also has great reviews and gives good energy and pumps but your body seems to build a tolerance to it quickly.
Higher Priced: Assault- gives amazing pumps and muscle endurance