Like the Discogs feature. An easy way to keep lists of your favorite shops within certain categories, areas etc (like "favorite second hand shops in UK" and so on..). Also very usable for inspiration for other users.
This could be very nice to have when the user profile functionality is developed further.
Yes I think this would be a good function for the site. It'll probably happen within the next few months.
Agree. Also nice for your next vacation.