Smart/curly quotes have been a thorn in the side for a while. When users of some browsers paste out of Word and into Movable Type (eg. for NGNO), the smart and curly quotes would come out as question marks (i.e. unrecognized characters). I had taught them to either turn off Smart Quotes or save as text, open in SimpleText or NotePad, and paste from there. They hated me for it.
Just found Brad Choate’s regex plugin, which lets your MT templates do search/replace on-the-fly. Configured it to replace curlies with straights, problem solved.
Of course, working with PHP would have been easier in a case like this — would not have needed a plugin to churn text; but the benefits of using a prefab publishing platform outweigh these occasional downsides.