I've worked in Library Science for 1.5 [evil forum can't handle fractions, apparently] years. I was just a library aide (making $12/hr), but it was the best job I've had so far (in my as-of-yet undegreed lifetime).
In our library system, at least, however, we keep busy. Of course, I hear we've got high circulation compared to the national average, but whatever. (On an unrelated note, I recommended Elantris to the Library, and we've got 3 copies on order).
Out here, it's hard to get a job as a Librarian without experience - one person with a Master's degree accepted a position as a Library Aide for a short while until she could wedge her way in as a Library Assistant or (if she's lucky), a Librarian. For the position of Library Aide I applied to alone, there were over 200 applicants.
Overall, I found it a very enjoyable thing to do while I was trying to save up and get through college, etc. Personally, it's not for me as a career, but it's better than a lot of the jobs out there, and the people I worked with were great.