The 1877 gazetteer is a very important resource to me, I use it for all my Hungarian research. János has it organized by counties (megye), and then sorted alphabetically by district and then place name. He then gives the church parishes in which the town residents would've belonged. And the best part.. he links directly to the Family History Library Catalog, if microfilms are available for the parish.
The 1900 gazetteer is new, but looks promising as well. With this project coming from János, it'll no doubt end up just as great as the 1877 gazetteer.