Here are some considerations when you are making decisions about book formats and distribution methods.
Hardcover – Ingram Lightning Source / Spark will print hardcover books as Print-on-Demand (POD). However, it can be expensive if you make them returnable, which is an option generally needed for bookstore distribution. As of this writing, Amazon CreateSpace does not offer hardcover printing. Many short-run digital printers will, usually at a premium. Time was, hardcover publication was necessary to solicit book reviews from mainstream media. But those reviews are diminishing in importance at that same time that even traditional publishers are issuing many new titles only as trade paperbacks.
Trade Paperback – available from the POD vendors mentioned above
Mass Market Paperback (pulp) – Generally not an option for self-publishers because typical print runs are huge and distribution is to large national retailers.
Audiobook – Amazon Audible www.acx.com – A site where author/publishers and producer/narrators can hook up to make deals, produce audiobooks, and get streaming MP3 distribution.
DVD – Amazon CreateSpace handles a Print-on-Demand version of DVD production and distribution.