Erythritol. Expensive as all heck, but, has all the advantages one could want from a sweetener: no aftertaste, granules like sugar, no/low glycemic index and naturally derived
I order though amazon.com. They have so many flavors. I use sweet leaf. The vanilla stevia by NOW is not good. That one is usually available in stores, but it is terrible. Sweet leaf also makes the best, IMHO, packets of stevia. It has added fiber.