Try to get the specs on the pumps you are considering in terms of liters/minute, maximum pressure, current draw and power in watts. There are some of the really expensive pumps where you can preset an auto shut off at a certain pressure (Bravo 12 and Bravo turbomax air station).
As a general rule, it is more difficult and costly to get a high output pump that runs on 12 volts than on 120 or 220 volts. As for 12 volt pumps, the ones with any substantial current draw need to be clipped directly to the car battery rather than the cigarette lighter.
The bravo turbomax seems like a fantastic 12 volt pump (1000 liters/minute, up to 4.5 psi with preset auto shut off - description here: http://www.bravo-pumpar.se/skikart.htm
), but it's crazy expensive and nobody in North America seems to carry them.
What I ended up purchasing is a high volume reasonably high pressure (3.0 psi) 120 volt pump (220 volt versions are no doubt available) and picking up a 1000 watt DC-AC inverter that I hook up to a spare battery I had.
Here is a link to the pump I purchased: http://www.sportsstuff.com/dyn_prod....6e951ea8db31f5
I paid $ 75 CDN for it (approx 35-40 British pounds).
I'm not certain of the exact amount, but I believe it pumps at a rate of about 1500 liters/minute. It will blow up my 4.2 m Zodiac SIB from completely flat to 3.0 psi in less than 2 minutes (will time it next time). From there I top off the pressure to 3.4 psi with a foot pump. The pump puts out 917 watts and draws 7.8 amps @120 volts.
Having the inverter and extra battery will also be handy if I want to use power tools in locations where I might not have access to a wall outlet. I also don't have to worry about draining/damaging my truck's battery since I run the exta battery & inverter separately and simply trickle charge it between uses. I will eventually pickup a deep cycle dry cell or gel cell battery to use with the inverter.