Waiting for FTDK's reply where he lists the current 12 devices he uses in flight!!!
Except for maybe getting a frequency, the iPhone is only of use as a novelty. Like Jaba, I have Jeppview & Avplan. I like Jepp better, but the overall integration of Avplan with flight planning, etc will ultimately win.
Depending on the complexity / expected difficulty / knowledge of airports my backup may include:
iPad
Jeppview on Motion CL900 tablet ( Jeppview is starting to look very old & clunky but it's in flight page is still best).
Paper print outs
PC with Jeppview in my briefcase.
Garmin 496
When I finally upgrade to a new iPhone with the new connector, I'll upgrade the iPad also. I think this will be the trigger to move back to the dark side with AsA and just use Avplan, which is a pity because their chart layout is generations behind Jepp.
If you have a Jepp subscription, putting Jeppview on a cheap windows tablet is not a bad backup option.