Art, I haven't used FileZilla. Enrique said that it has a feature to resume a broken download queue, but couldn't find a mention of this from FileZilla documentation.
I don't think the keep alive -feature helps here, but doesn't hurt to try. It's designed to not to disconnect when idling, downloading lot's of stuff sends messages to the ftp server "all the time".
Of the ftp programs I like
FlashFXP the most. It's not free, but there is a 30-day fully working trial. It also has a download queue feature, and it reconnects and resumes the downloads if the connection is disconnected. You can set it to reconnect X times, waiting N minutes between the tries. You can also queue stuff from multiple different servers.
The wget solution might not work for you if you don't have the bulk of the files already.
Another thing that I do when downloading tons and tons of files is just to download them one folder at a time, it wears the "butt muscles" but doesn't break the connection so often.