I don't yet know how much of a factor all the extra-curricular activities will have on residency selection etc.
Use a bit of common sense though. There are a lot of students signing up for every club/activity/etc, in hopes of making their CVs look good. I doubt it has that much of an effect. You would be better off to pick a few that you are really interested in and be active. By this I mean that it would look better for you to have fewer "activities" listed, but show that you actually did something. Be the club president. Turn the club around, or lead it to some big event. Have an impact. Be a leader. This will likely count for more than listing a bunch of activities that you were peripherally involved with.
Only my 2 cents worth.