Based on the info you provided, $10K budget, no 1 ct solitaire ring, desire to own one, and resale value and ease of upgrade of 1ct solitaire diamond, I would definitely get a 1-ct diamond ring.
A solitaire ring, especially with size of 1ct or larger, is very desirable. In terms of appearance, it is elegant and significant. In terms of function, it is very versatile, matches any kind of outfits, and can be worn in any occasions. You get lots of mileage with it. In terms of value, it can hold ts value much better than any other jewelry. If you select top cut diamond, you can more easily resell it for upgrade or change of mind than VCA or Cartier jewelry of the same budget.
In case you decide to get a solitaire ring, I have the following suggestions. 1. Ask Ame to find you or recommend top cut diamonds (1ct, I color, VS-Si 1 eye-clean clarity). 2. Get the Vatche U-113, 6-prong platinum solitaire setting. It is very elegant looking, and comfortable to wear. The setting allows the diamond to sit at the right height, maximizing size appearance without catching clothing. 3. If necessary, stretch your budget by 5-10% to get the diamond and setting combination. Trust me, you won't regret this purchase and you will enjoy this ring forever until you are ready to upgrade diamond size. In this case, you can change the head and still use the same setting.
