I've got to find more space in my Trailblazer for vacations and camping. I'm very interested in getting a roof rack, but I've really never used one of these before and I suppose I have all the same concerns that everyone else has. If you have a roof rack on a truck or suv, what type do you have and how do you like it?

My concerns are that it will be hard to get it, how can I know that it's really secure, does it cause a ton of drag and less MPG, and how well can I lock it down so I can keep stuff in there should I go camping and I don't want to find that someone opened up a branch of midnight motors in my neighborhood?