If you're not planning on spending much, this Plush Knitted Hat will fit the bill. It's a foolproof choice, while not very costly. Another strong contender for your wardrobe is this Hat. While the price of this product is rather reasonable, it will definitely attract a lot of attention. You might also want to consider this Replay Beanie. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you want to splurge, consider buying this Burberry Hat - a great luxury choice. While you're at it, also have a look at this Eugenia Kim Hat. Yes, this item is expensive, but it does not mean it's not worth it. And how about the luxurious Rick Owens Beanie? Yolo, right?