I am using Cronometer, I used to use the calorie king app for PC but it is no longer supported and wont work on my current lap top.
Cronometer is very flexible and tracks a huge amount of info and each nutrient can be set to custom values or left at standard. Most of my food is fresh but I just scan barcodes for stuff which isn't. Also get choice of region because nutrition labels vary with country, eg. in the US total carbs are listed plus a fibre listing, however here in Australia the carb value listed is Net carbs (Total carbs - fibre) so fibre is not required to be listed.
Definitely the best tracking app I have ever looked at, far better than the most common ones used by members here eg. MyFitnessPal which is a monster to use if you want to set targets in grams rather than a %
Will probably sign up for the gold edition so I can export custom reports