If you want to keep the DSB then
none of the critters anyone listed are DSB-safe! A properly constructed and maintained DSB is a fantastic thing, but most people do not maintain it properly. Yours is a fine example. A properly running DSB will not need to be vacuumed. Consequently, if you are disturbing the sand bed when you are vacuuming you are further damaging it.
Ron Shimek recently wrote a great article about DSB in the Coral Magazine entitles Dragonets (Nov/Dec 2011). Ron Shimek is definitely the DSB expert of the hobby. If you don't have access to the Coral Magazine (you
can order back issues online) you can check out Ron's website.
http://www.ronshimek.com/deep_sand_beds.html
On the other hand, if you decide to remove the DSB it can be done fairly easily and with low risk provided you don't remove it all at once. I like to use a 5/8" siphon hose which I use to remove the far right 1/4 of the sand bed making a nice straight line in the sand. Immediately replace with very well rinsed sand at the new depth. Make sure you cover any exposed black portions of sand along the edge of old sand that showed up when you siphoned the old stuff out. This is very important because those black portions of sand are
unhealthy anaerobic areas that can poision your tank if left exposed.
In one week do the same thing for the next 1/4 of the sand bed. If you do it slowly and replace the sand as you go like I describe you will have no problems.
If you remove the old sand bed, don't add any new critters to the sand bed for at least a few months otherwise they will starve in the new somewhat sterile sand. Once the new sand bed is established, I have found Fighting Conches,
small Nassarius snails (not the big Tonga ones), and Cerith snails to be very good sand bed cleaners without over-cleaning the sand bed and making it devoid of life like starfish can and will do.