I use the www.fatsecret.com website. It allows you to customize what you want to track (I choose to track fiber and net, but I had to specially set it up that way). Real foods (veggies, meats) reflect USDA values which are said to be most accurate.

There is also a huge database of processed foods. I don't use those very often, but when I do I check with the labels to verify that the correct information has been added on FatSecret by other users (or hasn't been changed by someone!).

Fatsecret also asks you what sort of plan you are following when you set it up and customizes messages to that plan. No low fat drivel coming my way.