Matthew, I don't have any experience with the 'large Postgres dataset' part of your question, but in my little OACS sandbox I have used BrioQuery (general end-user query/analysis tool) via ODBC to access the Postgres database. That gave me the capability to do all the Quicken-style slicing, dicing, drill downs, tabular reports & graphical analyses, plus arbitrarily join tables in creating new queries via the BrioQuery GUI.
I tried unsuccessfuly to lookup a ballpark cost to post here (from http://www.brio.com/). I have used BrioQuery for years, but Brio Inc seems to have buried the BrioQuery tool into their enterprise offering these days and a search for the term BrioQuery on the Brio website got me no results. Interestingly, a Google search brings up scores of universities that post their own local guides to using BrioQuery, so it seems to be alive and well out there in the wild.
But Brio is a rabbit across the path here, my real message is that ODBC access to Postgres was easy to setup and worked well for me (one user, small scale) which opens the door for numerous end user access options.
