I have to agree with you there Curious One - very good point. I have been blessed enough to work in IT for the last 2-3 years. If you are not happy doing what it is you want, then you will never give 110% just as you would if you were in the career that you really wanted to be with. It was something I dreamed of for a long time. I had the interest in IT since I was a young kid with my Commodore 64! :D
I've been lucky to have 2 careers that I love dearly and the best advice I can give you about chosing a specific area to study is to go with your heart. Do what you love to do. If that's security...great but if it isn't....I'd rather make slightly less money doing something I love than a lot of money doing something I hate. When chosing a field, you have to want to get out of bed everyday to go to work for 30-40 years. That's a long time to do something you aren't passionate about.