I have paid at least some of my dues in the professional development department. A couple of years ago I finished an MSc in Library and Information Studies gained with The Robert Gordon University. I chose this course as many others do because I could do it whilst working and it is accredited by CILIP. I was working at the time in an information role already but wanted to improve on my professional qualifications. I also worked a late evening every week in an academic library.
To be honest, I wouldn't advocate doing it this way -working full time plus part time job plus study did not make a good combination - I had no life for three years and I was exhausted after the first year. However I was delighted to finally finish and receive my MSc with distinction. I did have a lovely supportive partner who shoved food and cups of tea under my nose occasionally, but if you're thinking of studying along with a demanding full time job (I used to do additional evenings/Saturdays at certain times of the year), think about how you're going to cope with the sheer amount of work you have to put in, and with the likelihood of having to take quite a chunk of your personal leave as study time.
What I'm saying is this - don't do it unless you really, really want to.
The MSc didn't really help me with my library/information career to be honest. There are so many people out there with library qualifications now, I think experience count more. Employers have their pock of library qualified people. Having said that, having done my own research was a definite plus when it came to my current role - I've have a good solid understanding of how research works and is carried out.
I'm now attempting to charter, which as I've said before elsewhere on this blog, is a challenge when you're not in a traditional library role. I'm hoping that the chartership board will be keeping an open mind when it comes to the variation of information roles out there! I think this variation will become more common in this economic climate, and qualified librarians have to look at roles which they perhaps wouldn't have considered a few years ago. It's taken me a while, but I think I may see light at the end of the tunnel...