What can I do with Dragon Bones and Scales?

I've started slaying dragons (like all good Dohvakiin must), and with each beastie I down, I'm getting close to 200 lbs of loot, mostly in the form of Dragon Bones and Scales. These two items are high weight, and high value, but I can't seem to find any actual use for them, especially since most of the shopkeepers I talk to aren't interested in purchasing them.

Are these just supposed to be for decorating one's house? Or is there some nefarious purpose for them down the road that I should stockpile them for?

Trevor G is correct, they are used for creating Dragonplate and Dragonscale armor, as well as Dragonbone weapons.

To craft the entire Dragonscale set, you'll need 10 dragon scales. If you want the Dragonscale shield as well, that's another 4 dragon scales. You'll need an additional dragon scale for each of your Dragonscale armor pieces in order to improve them.

To craft the Dragonplate set, you'll need 12 dragon scales and 5 dragon bones. The Dragonplate shield is another 3 dragon scales and 1 dragon bone. Dragonplate Armor and Shields both need a dragon bone in order improve them while Dragonplate Helmets, Gauntlets and Boots need dragon scales.

Additionally, as of the Dawnguard DLC, they can also be used to craft weapons as well. These are largely forged from Dragon bones, leather, and Ebony ingots.

I was wondering the same thing and found this wikia page. According to the article, you can craft dragon bone armor once you become a master at smithing.

http://elderscrolls.wikia.com/wiki/Dragon_Bone_Armor

You can sell them at Belethor's general goods in whiterun, its just past the smith on the right as you reach the well

Early on, the best thing to do with dragon scales and bones is to sell them to a general goods merchant. They're too heavy to consider hoarding (without exploits) until you've purchased a house, and it's likely you'll get more scales and bones than you'll need for crafting armor (if you decide to spend the perks in smithing to unlock dragon armor).

While you can make more money by saving up your dragon scales and making armor after you've mastered smithing, money is usually more of an object early on in the game, so there's no real harm in selling them until your smithing skill is getting close to maxed out.

The bones especially are something to sell frequently, as you'll get just as many bones as scales, but the light "dragon scale" armor requires only scales (14 for a full improved armor, plus 5 for the shield), and even the heavy "dragon bone" armor requires more scales than bones (13 scales and 6 bones for full improved armor, plus 3 scales and 2 bones for an improved shield).

You can take a dragon bone and scale (one each) to Esbern, a Blade at Sky Haven Temple (if you did the quest).

He will make you Esbern's Potion, which supposedly reduces damage dealt by dragons by 25%.