Such as:   Splenda Artificial Sweeteners Sugar "In the Raw" Honey Stevia Molasses   Can they be used interchangeably in recipes or do they have to be used at different proportions?Aside from nutritional differences, can I expect drastically different flavors? 
The various artificial sweeteners and stevia can in general not be used to feed yeast or produce caramel. Most are much sweeter than sugar. They are controversial in regards to health effects, but then so is sugar.  The various "raw" sugars can have very different flavor profiles, as an example dark muscovado sugar often imparts a licorice note.  Agave syrup is somewhat "in" because of relatively low GI and should be added to the list. 