Just to add my $.02, while what much of what Fr_Chuck has to say is correct, it makes the job sound pretty boring...
Personally, after spending many years training to become a research scientist/professor, I made the career change to forensic scientist a couple of years ago and so far it is a better job than I ever could have imagined.
To get the most out of this job, first and foremost you really have to enjoy the science, espeically applied science. But the great thing about this job is the diversity -- I need to know about law, understand criminology, and do an awful lot of teaching (I train officers, MDs, nurses, attorneys, etc), which I also love. In addition to that, I get to testify on my areas of expertise in courts of law, which is also very exciting.
The only parts of Fr_Chuck's experience that are not accurate for me are that I often do know the outcome of the case, and in fact I am often instrumental in determining the outcome. Also, though I rarely go to crime scenes, those that the forensic scientist is required to attend are usually the most high profile and interesting ones, where our knowledge and expertise are most required. That said, I work in Canada, which has a slightly different system than in the U.S.
Anyhow, there is lots of good advice above, but be aware that both professions can be very difficult to get into. We generally get about 300 applications for every job advertisement, and have the luxury of mostly hiring PhDs or people with many years of experience for our scientist jobs. The best way to get in is usually by spending several years as a technologist, and then attempting to get a scientist job. As for veterinary college, up here it is harder to get into Vet school than Med school, although again, that might not apply everywhere.
My advice right now (note: This is subject to change depending on my mood and the time of day!) -- if you love school, keep going in an area you truly love until you decide it is no longer for you, and then look around and see where your skills will take you. Of course, it is probably a pretty good idea to stick your head up every now and again to make sure that careers actually exist in your chosen field, otherwise you'll be like a few of my friends who are incredibly brilliant, have more credentials that you can imagine, but are completely unemployable anywhere other than the world of academia!

Originally Posted by
Fr_Chuck
...in most departments it is the police department that takes the evidence at the crime scenes and sends it to the lab. The lab people never leave the labs and go tot he crime scenes.
Only in the very largest cities would they have field investagators who went tot he crime scene to take evidence and only on the major crimes.
Next the crime lab people would never ( never) actually question the witnesses, they would merely turn reports over to the police who would question the suspects.
And no they don't have two or three days or weeks to work on just one case. For example they may have 10 cases or more a day to process, they just move from one case to another.
And in many cases they will never know what the outcome of the case was.