Olive Oil

Among the most frequently asked questions chefs are bombarded with is What kind of olive oil should I buy ? The correct answer is the best you can afford. That being said there are a multitude of choices on the market. I would personally estimate that 25% of  olive oils in retail stores are well on their way to being rancid due to climate and storage issues. Find a brand you like in a retailer that cares about how oils are stored in terms of temperature and direct light. Outside of those issues, taste perception varies. The number of answers you get will easily be 3 multiplied by number of people you ask. Here is what I currently use.
Planeta from Sicily for most meat and earthy vegetable preparations.
It is very compatible with autumn cooking.
Powerful peppery finish.

Marques de valdueza  from Extramadura for lighter fish and floral vegetables.
Lucious buttery flavor, great year round olive oil.

Armando Manni's  twin tuscans for finishing more refined preparations.

Frantoia oil for all other basic cooking.

Colonna citrus oils are also great finishing oils for cold shellfish preparations or vegatables that benefit from a final aromatic element of citrus fruits.