There are two books that are particularly useful for identifying Indo-Pacific stomatopods. The most up to date is Shane Ahyong's "Revision of the Australian Stomatopod Crustacea" published as Supplement 26 to the Records of the Australian Museum. (2001). I purchased my copy directly from the Australian Museum. It wasn't cheap.
The second book is Raymond B. Manning's "Stomatopod Crustacea of Vietnam: The Legacy of Raoul Serene." It was published in 1995 in Crustacean Research, Special Number 4. This is a publication of The Carcinological Society of Japan. It is a beautiful volume that contains several color plates of watercolor illustrations prepared for Serene by Vietnamese artists. I have no idea how you would purchase this issue. I was given a copy by Dr. Manning when he was still alive.
There is nothing comparable for the Atlantic although there are several keys published by Manning, Camp and others. Manning's 1969 "Stomatopod Crustacea of the Western Atlantic" published as Studies in Tropical Oceanography No. 8 by the Institute of Marine Sciences, University of Miami, is dated, but still very useful. I bought a replacement copy a few years ago by contacting the Institute of Marine Sciences directly.
I would generally have to say that the most interesting stomatopods are the ones I'm studying at the time. That said, I do have a particular liking for the smaller species of Odontodactylus (O. brevirostris, O. havanensis, O. latirostris and O. cultrifer) as well as for Echinosquilla guerinii. The odontodactlylids are some of the most alert and interactive of all stomatopods with incredible communiction systems. E. guerinii with its sea urchin mimicking telson gold reflecting eyes is just plain weird!
Roy