There are now several low carb bars on the market that are chocolate with crisps - like the Nestle's Crunch bar style. This being my favorite bar style, here's a summary.
Hershey's bar is just called "carb" and is chocolate candy with soy crisps. It has 1g sugar with the rest being sugar alcohols (9g) and fiber (6g). There are 6g saturated fats and 0g trans fats. There's both erythritol and sucralose being used to sweeten this.
This is a thick, meaty bar at 1.1oz and has a solid milk chocolate texture with big, weighty crisps. The flavor was VERY mild though - both in the chocolate and in the crisps.
The Pure De-lite bar is called a milk chocolate crisp, and is made from Belgian chocolate. This one is 1.1oz, has 3g carbs, with 11g of maltitol and 1g of fiber in there. There's no other sweetener besides maltitol. There are 6g saturated fat and no trans fats listed (meaning maybe it's 0 or maybe it's 4g).
This is a much thinner bar, more like a gourmet chocolate with small, delicate crispies in it. The flavor in this bar is MUCH richer and smoother, much more like an elegant chocolate experience with great, tasty little crisps in it. It's a bit on the powdered-sugar side of sweetness.
Carbolite At Last! Chocolate Crisp
The Carbolite bar is 1.0oz and is 2g net carbs. There are 6g fiber and 6g sugar alcohols - erythritol plus sucralose to sweeten. There are 6g saturated fat with 9g total fat (not broken out into trans fats).
This was a very 'flat' milk chocolate bar with a mild flavor and crispiness. It was good, but not exceptional.
Z Carb Gourmet Dark Chocolate Bar with Soy Crisps
Z Carb is amazing because it claims zero impact carbs. The actual number is 0.007g which is pretty much zero, with 9g fiber and 3.993g of sugar alcohol (erythritol). It's also got splenda sweetening it. There are 7g saturated fat and a total of 11g fat.
I *really* love this chocolate bar - the chocolate itself is rich, smooth and dark chocolatey, and the crisps are quite tasty. This is a hard bar to find, though, so stock up if you see them.
These bars are definitely FAR better for you than eating a sugar-rich chocolate bar, so give them a try and see which matches your palate! I personally would go for the pure de-lite or Z-Carb for those times that I have a chocolate craving, and savor every bit.
UPDATE: As of 2008, it looks like the Z-Carb bar has been discontinued. That's so sad!