I use Airnav Pro, currently without paid charts because I still have some valid paper ones. I'll stay either with Airnav Pro, or go with Jeppesens Mobile Flitedeck VFR. Jep's price is a bit steep however, so I'm waiting until next year to have a bit of reviews from other pilots first.
For aircraft performance calculations and an E6B I use Gyronimo products.
I also email preflight bulletins (with Notam and weather reports) to myself when doing flight preparation on the laptop, so they will be automatically on the iPad through iClouds.