Does anyone use one? If so, do you recommend an app or website that calculates the calories per gram or ounce in food?

Yes, I use a digital scale. In practice though, I find packaging for even fresh meat etc from the supermarket tends to have to have the calories per ounce or per 4 ounces or whatever on it, so I go by that x my scale results. I also primarily use frozen vegetables because I am hyper-vigilant about waste and not being locked in to using up fresh vegetables that I have within a certain amount of time. Frozen vegetable packages tend to have the calories per cup, so I go by that. For everything else (fruit, when I do have fresh vegetables, or other items without packaging), I tend to use fatsecret.com, just integrated with the rest of my tracking. If it's something I'm iffy about, sometimes I will compare the googled results from myfitnesspal, caloriecount.about.com, etc.

I have one and it weighs in ounces or grams. I got it from an online shopping network, I forget if it was QVC or HSN, but the brand is Wolfgang Puck.

I have the OXO digital 5lb kitchen scale w/ pull out display and I have no complaints about it. I got it on Amazon. There are versions with higher weight capacities but 5lbs has been fine for my needs. I mostly use it for weighing out portion sizes.

I've had 2 Salter brand scales and hated them. The battery died within days on both of them even after replacing it several times.

I use LoseIt for calorie and nutrient tracking.