I used to use FitDay, until I discovered DietPower
and I FAR prefer it. I've spoken about it here and elsewhere, so if you've already heard me talk about it, then stop reading now.
It is not free after the first 2 weeks (after the first free two weeks, it's like 40-50 bucks to own the software on a disk - so you can install it on more than one computer and then transfer info back and forth between them to remain updated) but you don't have to be online, it does SO much more than FitDay, and it is much easier to use in many different ways. It's won a bunch of awards, and has been recognized by some different health/fitness mag's and organizations, and has a forum and great technical support.
It tracks your metabolic rate, adjusting daily based on your weight, exercise, and caloric intake, among other things. You can set weight loss goals and it projects your anticipated results in comparison to the goals, complete with graphs.
You can customize your exercise, adding exercises that are not in the database, and it modifies the calories burned as you lose (or gain) weight.
In addition to having a huge database of foods and the ability to customize foods, you can create recipes, then indicate how many servings are yielded, and it breaks down the micro- and macronutrients for each serving. You can keep a section for favorite foods (and vitamins, etc.) and then just drag and drop the items into the new day's entries.
It has calendar, calculator, and journal functions. It has a huge library of information on different nutrients, including which foods are rich in them. It tells you where your nutrients are lacking (based on customizable nutritional goals -- like for instance monitoring your sodium or sugar) and then makes recommendations for foods you like based on previous entries.
It has so much more that I couldn't possibly go into here. Suffice to say it rocks, and I just love it!!! FitDay is cool, but DietPower is just in another category altogether.....another level of product. Also, they offer discounts on different products -- so I got my Tanita food scale and body fat scale, as well as my pedometer at a good discount. I would have gotten those things anyway, so I sort of mentally applied them against the cost of the software. For me, the cost has absolutely been worth it.....I think of it as the cost of a decent dinner out with my sweetie, and so spending that money in this way is certainly worthwhile.