If you don't know what you really want, trying to choose a major NOW is silly. I changed majors 5 times and wound up taking an extra year to finish university but having a helluva time.
My recommendation: If you have a general area (arts, science, engineering, etc.) make that your major in first year but take lots of electives from other areas that interest you and if you have time, audit even more courses.
Jordan - for the record I don't think you've thought things through in sufficient detail in order to rule out your other interests.
Biology - your uncle is right, in pure biology research type stuff, jobs can be sketchy. But if you want to do something other than pure research there are lots of options. You could make it biochem and go make assloads of money at Pfizer. You could use a biology degree as a stepping stone to med school or chiropractic or some other health field. I know a guy that dual-majored in biology and marketing and went to work running advertising campaigns for the agriculture industry. LOTS of options there beyond what your uncle is talking about.
Athletic Training - maybe the money's not there for a schlub trainer at the local toning gym but for the motivated, there's always money to be made. What if you did a kinesiology degree and then maybe went to work for a professional sports team as a trainer? What about exercise research? Does THAT interest you?
Psychology - the degree to which you've generalized psychology is truly appalling. Clinical psychology (dealing with the mentally disturbed) is only one of MANY aspects of psychology. Hell my degree is in Organizational Psychology. Behavioral Neuroscience could combine your biology and psychology interests. Developmental Psychology is a place to go if you like babes because the babes like studying babies. Cognitive Psychologists at my school worked with the Computer Scientists in developing models for artificial intelligence. Social Psychology is a lot like marketing... understanding why people make decisions and theres crossover with sociology. Clinical psychology, while it's the most popular conception of what psychology IS, is likely to be less than 20% of the curriculum at any decent psych school and you may not even have to take ANY courses in it (I didn't have to although I did -- and decided I didn't want to be a clinical psychologist because listening to people whine all day sounded lame. Of course, now I admin here at WBB and get to read threads about people whining all day. But I can walk away from the computer...).
Criminology: My best friend in the world has a degree in criminal justice and law enforcement. He worked as a SECURITY GUARD for many years and now repairs slot machines at a casino. I don't know how it works in your area, but here in mine if you can't pass the exams to get into the police college then you're S.O.L. for employment with the OPP (our 'state' police) or the local 5-0. Ditto the RCMP (our version of the FBI). Personally, if I were in your shoes and I was set on trying to be a cop I'd do the psych degree and take some criminology electives. At least that way if the cop thing doesn't pan out you have something to fall back on.