No to tables
We need to get away from tables in epubs and think of different ways of showing data. The devices were designed to give the user a degree of control (e.g. increasing text size) and therefore tables are a bad idea in these sort of documents.
I recently had to do my first epub which was full of tables but we had a rethink and decided lists were better. They gave us more flexibility and with some clever CSS use on the sub-headers, it looked a whole lot better.
Turning tables in to images is a really bad idea. If someone is having the epub read to them by the device, it will just read "image" and not the details from the table!