There are two 'major' brands now that are a processed stevia to remove the naturally bitter aftertaste, they are Purevia and Truevia. (Minute Maid and Tropicana and their owners Pepsi/Coke both had extensive hand in their development process and ensuring sales for their low sugar juices)
I use them but am a bit skeptical of the process I have my eyes open however, there is also Stevia in the Raw from the same company that makes Sugar in the Raw, and it is more pure, raw form.

I would also recommend to you to check for a Xylitol based sweetener, it is natural and VERY good. I have used it extensively, it is also popular in Asia, AND it is a naturally beneficial anti cavity aid, and natural toothpastes are many times now based off xylitol, and work REALLY well. I use NOW Foods Xyliwhite, and burt's Bees all natural fluoride free toothpate made with Xylitol. Many dentist are finally opening to the natural anti cavity benefits of xylitol and recommending parents to have children chew xylitol gum once a day.

"Ideal sweeteners" (a brand) are xylitol based, but watch some of them, they blend with surcalose (splenda) on a few.

I just saw for the first time and bought, small packages of Agave nectar sweetener as well. I have used Agave nectar as a replacement for honey and corn syrup for years now, so it will be interesting to try it in tea and other places, but I haven't opened it yet.
Here it is: http://www.xagave.com/Individual-Agave-Packets/