Organic Stevia is a good sweetener. You can get commercial brands of stevia in some supermarkets and health food shops but I haven't looked into the healthiness of the extraction process for commercial brands or whether they use unhealthy additives.. I buy organic Stevia powder online and it's fine in baking (although it does give a slightly green tinge if you use a lot) but it's an acquired taste in some hot drinks. I've grown to like it.
You can get organic coconut sugar which is a really gorgeous sweetener and smells/tastes a bit like demerara sugar. In a 4g serving, approx 1tspn, there are:
15kcal
0 fat
0 cholesterol
9mg sodium
4mg total carbohydratw
0 protein
It's low GI and high in magnesium, potassium, zinc, iron and b vitamins. The brand I use is Coconom organic coconut sugar. Yum!