Get the Dearborn "Drill and Practice" CDROM. They have hundreds of drill questions arranged into subjects, plus simulated full exams. When I took my S7 I used this cd, the arrangement of questions into subjects was priceless. Many of the questions appear in the actual exam word for word too. Got a result of 91%....
I have to disagree with this comment. I am using the STC manual and classroom (1 week, $395 total) and the online Series 7 Practice and Exam module ($75) from Dearborn and also a study guide from Thomson-Southwestern ($75-don't buy). The STC manual is definitely the best. But the online course from Dearborn is really good for practice. You can customize your practice exams and final exams any way you want. Like using questions you got wrong or question that are new, etc... It is a real help in learning the material.
STC + STC progressive exam CD if you can pass those tests, you can pass the real one. STC overprepares you. S7 took me 2 1/2 hr.