Lately I haven't watched anything made later than 1940, so it would either be Gold Diggers of 1933 or 42nd Street (also 1933) on DVD - I watched them on the same day but can't remember which I watched first or second. Anyway, I rate both at 10/10 because Busby Berkeley + Ruby Keeler cannot equal anything less than perfection.
Next up (probably tomorrow if Amazon are on form) Dames (1934) - because I can't get enough of Ruby!
(Note: before anybody asks, I am not old enough to have caught the premiers of these movies. My mother was born in 1933, so even she had to wait a few years.