Currently I use a standard PSTN or POTS handset VOIP phone connected to a wireless VOIP cable router and DSL modem. These are all powered through a UPS. The UPS should maintain the DSL connectivity for around 5-6 Hrs continously. Internet connectivity can then be accessed using a wireless connection via an Archos hand held media player.
Additional devices such as SW radios, portable digital TVs, Desk lamps etc can be powered using the UPS, again for short periods. A mobile phone can also be powered using a conventional charger.
If the UPS dies then the phone will switch to a conventional PSTN or POTS line automatically.
The next addition will probably be a Network Attached Storage NAS (rather than having the desktop PC switched on) to store all my media such as DVD, MP3s etc as the Archos also make quite a nice media streamer for the main large screen digital TV in the downstairs living room.
A future upgrade for the router may be required also to the Draytek Vigor 2910 or Draytek Vigor 2820Vn with 3G Cellular Data (3G backup) i.e. when the pricing for 3G connectivity becomes more attractive.