I've developed a thing for Lindt 99% chocolate which contains no sweeteners and is very low carb...
per 50g bar:
Fat 25g (Saturated 15g)
Carbohydrates 4g (Fibre 3g, Sugars 1g)
Only problem is that I've never been able to find it in the UK. Some people do booze-cruises to Calais, I do choc-cruises. Last time I went I picked up 50 bars!
It's only 1.80 euros a bar so it's economical.
I'm still looking for some good 99%/100% options in the UK that are affordable.
Willie's Venezuelan Black is 100% so contains no sweeteners but it comes in a big block and is very hard to just eat from the block. It's good for grating in recipes though.
You can get 100% at Hotel Chocolat but at £4.50 it's not cheap (for the amount I like to eat!!) plus it's more bitter than Lindt 99%
This site's got quite a good forum that has a lot of reviews of different dark chocolate....