It depends on your goals and plans. If you're trying to sell your property soon for the highest possible price, your priorities are likely somewhat different than if you're planning to stay for a few years and want to improve your family's quality of life.
If you're selling, focus on the renovations a buyer would be most likely to undertake, not those you're most itching to do. Buyers generally focus on kitchen and bathroom quality, along with overall living and storage space. Kitchen and bathroom remodelling projects are among the most disruptive undertakings, so buyers especially appreciate upgraded fixtures, appliances and décor in these rooms.
Here are ten worthwhile home improvement projects and the percentage of cost typically recouped at resale (in a seller's market)