Yes, you need to tell us if you have any valuable items that, individually, are worth more than £2,000, even if they don't leave your home. Examples of valuable items include jewellery, watches, furs, items made of gold, silver and other precious metals, pictures/paintings and other works of art, as well as stamp, coin and medal collections.
Although some belongings like your TV and sofa may be expensive to replace, these are covered as standard under your contents insurance policy, so you don't need to specify them as a 'valuable item' when you get a quote.