I've just retired after working in libraries for a total of 31 years. I started as a 'Saturday girl', shelving the returned books, progressed to full-time work as a Library Assistant in a Public Library -- then had 15 years out while I had my children. I returned to work in an academic library (and to a completely changed set of required skills, as computerisation had happened in the interim
).
I've worked my way up through the various qualifications and levels while working full-time, and ended up as the wonderfully-named 'Learning Resources Co-ordinator' (i.e. Assistant Librarian) of a large FE College, managing a team of 18 staff.
In all that time, I have constantly found that the general public see Librarians simply as people who 'stamp books and shelve them' and totally ignore the massive changes in working practices and skills that have been required - just as they think that all Librarians go round saying 'Shushhh' - despite complaining in the next breath that libraries are SO noisy nowadays.... 
The skills required for Librarianship are vast, and there is a wide range of areas to specialise in (e.g. archiving, conservation, restoration, cataloguing, use of computerised stock management systems etc.) and most of these areas equip you with transferable skills that can be applied to many other jobs.
I loved every job that I had, and enjoyed my work for all those years - especially as it changed so much and so constantly challenged me to learn new things. I'm especially glad that I worked with IT so much, so that can enjoy my retirement with none of the 'IT phobia' that I see in some of my friends. 