The black-box software testing courses offered by the Association for Software Testing are fabulous (and difficult). Well worth the cost.
What skill, course or education did you find most helpful to for your career in testing?
Very few people have an education specialization in software testing. Most of us arrived from a different path. What classes, specializations or skills did you learn that you find most useful as a tester?
tough question and no easy answer. I would susgest reading Lessons Learned in Software Testing by Cem Kraner, James Bach and Bret Pettichord
From my standpoint:
1. English and general communication (since I'm from Brazil)
3. Java and OOP
4. Curiosity and motivation to perfection.
I believe the following skills, course or education will be helpfull to make a career in testing
1 - Testing Fundamentals
2 - How someone can make a career in testing
3 - what's the technical skill set you need
4 - Domain knowledge or functional knowledge (based on which domain you are targetting, like Banking/Finance, Health case, Insurance, etc....)
5 - Automation testing Tools (like QTP, Selenium, Load Runner...etc)
6 - How to deal with defects (mostly the defect management)
7 - Techniques and process in Testing
8 - Mobile testing
the list will go on....