VotersUnite.org has a comprehensive database of election problems in the Nov. 2, 2004 election, sortable by state and type of problem. The list of voting machine malfunctions by itself is quite chilling:
VotersUnite! presents the following compilation of problems reported in the media about the 2004 general election. Starting with early voting, we are seeing a wide array of problems, some of which appear in multiple states. This page allows you to see how widespread the problems are as they accumulate.
They also offer pdf downloads with footnoted summaries of malfuntions and miscounts, separated out for each voting machine vendor who's machines had problems: