The answer for this question is sort of lacking, so I thought I'd fill in more thoroughly.
The triangle thingy indicates the item, among the various ones you're considering at the moment, that the game thinks is best. "Considering," in this case, refers to the items that are both in your inventory and the inventory of the container or person you're currently interacting with.
Items that you previously owned or that are in your chest at home, etc., are not factored into the game's assessment. The game's assessment is also purely statistical. That is, it picks the "best" item as the item with the highest relevant stat--for weapons, this is the damage stat; for armor, the armor rating.
Even if you're a sneak build, it'll still think the Dwarven Greatsword is the best, and heavy armor is always listed as better than light armor, unless the light armor in question actually has a better armor rating than the heavy armor.
The game does not assign triangles to items that are not weapons or armor. This includes magical amulets and robes--the former because it's actually not a type of armor, and the latter because of its de facto poor armor rating.
There are further subcategories within weapons and armor within which the game will assign triangles--that is, you'll not just have one triangled weapon and one triangled armor. These are, for weapons and armor respectively, bows, one-handed weapons and two-handed weapons and headwear, bodywear, handwear, and footwear.
To all viewing this recently. .
As A.C.M. noted, claw damage increases with character level but is not on a scale with damage from actual weapons. You will have 0 armor as a werewolf, so the damage output will not keep you alive. The fear roar does not work on higher level opponents; even bandits are immune at higher levels!
Essentially, after approximately level 30, werewolves are generally useless except for the disease immunity, which sometimes doesn't work anyway. The ability to carry large amts of gear is offset by their being unable to pick up gear, so it is of reduced usefulness. Sprinting is the only advantage and pretty much pointless in a game with fast travel.
Final answer: use a mod someone has made, mod the game yourself, or don't transform, since nearly everything can 1-shot you around lvl 30 or so.
Best Answer
Most of the Claws lose their quest item status (if they ever have it at all) when you complete their respective dungeon's quest.
If you choose to re-steal the Golden Claw, for instance, it will be a normal (albeit stolen) item that can be pawned off to a fence for quick cash.
Collectors might be inclined to display them in their house - there's at least 3 more claws out there in Skyrim, but at the end of the day, they're just loot. And what you do with your loot is your prerogative!