speaking of footer...

to have space between my footer and whatever body content is above it, I'd think that using margin-top would be the best practice, yes?

or padding?

Does it matter if the bkg is all white?

in the past, I'd have used <p> or <br>, I suppose that's outmoded

re: speaking of footer...

I can't think of any other.
the difference between padding and margin (in case of the background colour) is, that with padding you have the footer's background, while with marging you have whatever background lies underneath.

quite so

regards

re: speaking of footer...

I think it depends on how your page is structured. Putting padding-bottom on the wrapper containing the content, for example, will push the footer down creating a space between the bottom of the content and the top of the footer.
Does it matter if what background is all white? The content wrapper background might be white down to the footer, and the footer background might be a different color. Or both might have white backgrounds.