Which dithering setting best?

I am a complete know nothing on dithering other than knowing that it changes bit rates.  I have always left it at the default triangular setting.  Upon reading further I am led to believe that powr2 or 3 are better.  any input?

Thanks CJ for the reminder. 
I don't often convert down (since I use CD Architect to print my CDs) in Sonar, but that's especially good to know.

High and Dry,
It's about how digital music and bringing it down from say, 24 bit to 16 bit effects it overall. This reduction causes a truncation of information in your wave.  Dithering aims to reduce this loss to a minimal.  There are some pretty good resources out there that can explain this WAY better then I can, but dithering is more a matter of getting your higher bit resolution wave down to CD levels (44.1K, 16bit). Here is a quote from Brian Smithers article in EM Mag, "Try to maintain 24-bit resolution throughout the process, and dither when you bounce the mastered versions. Most good dithering software offers multiple noise-shaping options, so experiment with the different types to see which one is best for your music. Note that the differences lie purely in how noticeable the dither noise is in the context of your finished tracks."

Don't worry about which dither algorithm you use. It literally doesn't matter most of the time.

Nobody else can, either.