Audiofile's FiRe field recording app was already a useful tool for the roving producer, but v2 brings enough improvement to more than warrant forking out the price of a pint again.
The biggest new feature is audio editing (using technology from AE's Wave Editor Mac application), enabled by turning the host device on its side.
In audio editing mode, you can define, cut, copy and paste discrete regions of audio, and apply normalising, bezier fades, gain changes and DC offset removal; you can also create, move, name and add photos to markers.
A handful of EQ- and dynamics-based effects have been introduced (along with some new input processing presets), and analogue input gain can now be adjusted.
Plug in a decent stereo mic if the iPhone one doesn't cut it for you, and you have an incredibly capable portable recorder/editor.