Squats and lunges are awesome leg exercises. I call them "all purpose" exercises, in that they use many muscle groups:

legs (duh), but did you think about abs and back that are holding you up? also those arms holding the weights, they are stabilizing the exercise too.

Always be careful with body position especially the knees. this is the common error i see with people in the gym.

I am not crazy about hamstring machine exercises but try this one on for size: i give this one to my clients:

http://www.onlinefit.com/health/index.cfm/Exercise/381

it works the hamstrings as both a hip extender and a knee flexor, as well as abs and back. The glutes are worked as well but only a bit. It's awesome because there are so many variations to make it more difficult.


Have fun!

Han