My choice would be to shorten the content on the index/entry page.
That makes things more "cleanep up" IMO, better to browse through everything.
But leave all BBCodes intact, breaking/stripping the layout/formatting of text doesn't look nice either IMO.
I dig the way PhpNuke handles it:
You have two text areas to fill: a "teaser" that's shown on the list page and the "real" content shown together with the teaser on the page of the entry.
And I would not see how or why my administrative view on that would be different