FS/BS are fine, though you're going to want to work up to weight in FS. I do FS as part of my warm-ups, don't consider them a key lift. I'm about 100# below my BS weight for FS (~225# vs. ~235# or so).
For hamstrings: Glute Ham Raise. It's an under-trained segment for many people, IMO, and you can't do too much GHR. There's an excellent front-page article right now: http://www.T-Nation.com/free_online_article/most_recent/the_gluteham_raise_from_a_to_z
The image itself is worth a small fortune....
I'm not a huge fan of leg press, but I do some heavy high-rep work on the sled (15+ reps). Sissy squats will also work quads. Extensions and curls can be hard on knees, I'm not a fan.
What are your weak points in your squat? Hole? Lock-out? Mid-range? Depending on these, focus your training.
Box squats, hip/glute thrusts, and step-ups are other areas you can work. Step-ups will work glutes and hip extension while not overloading your back, they're also good for balance and balanced development.
I also like to do chins of some sort with squats just for spinal decompression.