Microsoft's Access is the top ranked PC-based (i.e., non client-server)
database management system available.  The Windows95 version is better than
the Windows 3.1 version and the next version promises even more.  It is easy
to use to develop simple applications (as is just about any PC-based
database management system, the easiest probably being File Maker Pro) but
the transition to multiple screens and more sophisticated functionality is
more difficult and time-consuming.  It does not have built-in record locking
mechanisms for simultaneous access by multiple users on a network (as do
client-server databases) and this function is not trivial to add yourself
(putting it mildly).

When designing your own system, there's a lot to be said for using a
mainstream product like Access or FoxPro from big companies as opposed to
proprietary or one-off systems such as OpenInsight, Systems Simulation, or
BASIS not the least of which is the availability of third party programs
that can be used in conjunction with these products and the widespread
availability of materials in bookstores on such systems and people who are
familiar with the systems in case you need help.
There is at least one commercial museum automation system based on Microsoft
Access -- SNAP! for Windows from WIlloughby Associates in Chicago.  It is
currently used in about 70 museums.