During and for a period after intense training yuor body becomes "starved" for carbs and protein as your glycogen and amino acid levels are in a "crashed" state. ie. you just used them all busting a vein in the squat rack. At this time your body is primed, so to speak, to process carbs more effeciently that at any other time during the day. Dextrose, fructose, maltodextrose, carbs found in grains, high GI fruits, etc. are best processed in the post work out window.
Studies also show more stable insulin response during this time, to the point where Type II diabetics can, in some cases, eat like they don't have diabetes and not suffer from insulin response problems. Type II diabetes can also be cured, or forced into remission, through intense exercise and proper body comp. Type II Diabetes appears to be more closely related to body comp and excessive carb intake than simple sugars vs. complex carbs. Type I diabetes is whole other ball game tho.
A couple of nutrition experts, who's information is backed by science, suggests eating starchy carbs, simple sugars, etc. only in the 2-3hr post workout window. At other times your carbs should come from low-mid GI fruits and all the veggies you want.
Reguarding when to take protein powder, anytime you need more protein in your meal is fine. People talk about Whey being a fast protein and say you should use casein instead. Well, Whey is faster than casein, but it still takes a while to get into your system, like 1-1.5 hours after comsumption (I think I read). Personally I have a protein shake and some veggies for breakfast (6-8hrs before workout) and one immediately after my work out (this one has a butt load of carbs in it too). My shake will have 1-2 scoops of protein, some cottage cheese, natural peanut butter, flax seed, frozen fruit, etc etc. NOt just the protein powder. Make a meal out of your shake, it'll taste a hell of a lot better than whey and water.
Finally, NOT ALL SUGARS ARE CREATED EQUALLY, don't hate on sugar for sugars sake. Stay away from highly processed sugars, like refined white, high frutose corn syrup, etc etc. But natural sugars, like those found in fruits and the like are actually good for you in moderation. I use a combination of stevia and honey to sweeten my meals now and have noticed a more consistant energy level since doing this. I don't spike and crash like I used to...