Should we change our opening hours?

If you've visited the Caird Library recently you'll know that in July and August we were on 'summer hours', where we close an hour later than usual at 5.45 pm. This is something that we now do every year to match the Museum's longer opening hours, and it seems to work quite well. Not many readers actually arrive in the last hour, but people do stay and take advantage of the extra time.
Now summer's officially over we're thinking about how different hours might work permanently. We're planning some market research in the next few months, but would be interested in hearing what you think now.
For instance, would a late evening opening really help you with your research? Perhaps until 7pm or 8pm once a week? If so, which day would be best?
Have you ever wished you could use the library on a Sunday? Or that you had 24 hour access?! (I know one public library that has an annual Family History Lock-in, where researchers get to stay all night.)
Would you like straight-forward research access or more special events?
Let us know what you think.
Jill (Head of Library and Manuscripts)