I prefer to give gifts that I think of as a result of careful listening. Maybe someone has expressed interest in something, but decides not to buy it. Or, maybe there’s something they’re passionate about, and I can get something related (though, this is dangerous, because usually if they are passionate about something, either they already have what you’re getting them, or they have already got their mind set on something even better, e.g. an L lens when you got them a standard lens with similar specs).
As for receiving, I like things that are not needs, and are something I really want, such as a video game or SACD I’ve been researching but don’t feel wealthy enough to buy.