Wow! that's a good question. I think "used to" is best used when describing a past action or situation that does not happen presently "I used to play baseball, until I broke my arm." While "would" in this context shows preference of past actions or conjecture based on past decisions or trends. So to answer your question, if the subject does not do the verb presently then "used to" is an acceptable option. If the subject has usually chosen a certain action (e.g. I would [usually] watch movies or go to the beach), then "would" would [usually] suffice.