What determine good carbs and bad carbs?

I know a little about carbs, I know some are considered good or bad. like the refined sugars i know are bad, such as icecream and all the really tasty stuff!!! :P I also know about the GI (Glycemic Index) I know about the high,medium and low ratings. So is it general rule that things with low GI ratings are good carbs? and ones with high GI ratings are bad?