12 volt battery as power source

It seems that battery powered devices could eliminate many issues caused by bad wiring, power grid inconsistancies, contamination from appliances, dimmers, etc. That said does anyone think that a 12v deep cell battery hooked up to a 110ac power inverter or similar set up could be a good thing in a power efficient set up?

deep cycle battery:
http://www.1st-optima-batteries.com/

12v dc to 110v ac converter:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50588&item=5703973901&rd=1