Sugar in either it's pure form or as a carbohydrare (complex or otherwise) is the enemy of the diabetic. For this reason it is best to avoid 'Sugar' where it is possible and there are easy sencible alternatives.
Being a Type 1 on Insulin will mean that you have to balance the amout of Glucose (Sugar) present in your blood against what you eat so that over time you acheive what are controled safe B/G levels.
Type 2's generally have what is known as 'Insulin Resistance' meaning that they (unlike a Type !) can produce Insulin, but what is being produce is either not being utilise properly, of maybe of inferior quality, or in a number of Type 2 diabetics often overproduced which can then lead to further problems.
We all break the rules from time to time with that occasional sugar based treat, but it should remain an occasional treat.
As Brett says - Non Diet Sugar based drinks should be considered a No-No unless they are giver to someone experiencing a Hypo, so please stay off them.