For those who aren't aware, an ideal ratio for a "landscape" rectangular orientation is 4:3, the ratio of most computer monitors (no matter what their resolution or size.) IOW monitors displaying at 1024x786 and those displaying at 800x600 both have the same ratio. This might sound very basic or tangental, but it helps to become familiar with how the 4:3 ratio translates at different sizes when planning your test renders vs. final pictures. Shrinking an image's size isn't the same thing as anti-aliasing, it just has a similar perceptual effect. I used to overdo it: I'd render at 3Kx3K when the finished product was 800x600. At that large of a difference, much of the postwork I did was unnecessary (e.g. guassian blur on edges.) Obviously those working in high-quality print and TV media will want larger resolutions, but for computer-only use it seems like rendering at merely two times the size you intend the finished product to be is fine.