Beautiful URL, which is better?

For a long time the question has been tormented how to better name directories:
site / user s / or site / user /?
Because on the one hand the list of all users, photos, files, etc. is / users /, and on the other hand, if you open a specific object further, then / users / vasya / is not as beautiful as / user / vasya /.

The same for / photo (s) /, / group (s) /, / file (s) /