i find that with screen resolutions getting pretty high these days and the properties not changing to accommodate them, a solid border looks like an inset/outset/ridged/double/groove unless you make the border-width quite wide but then it would look bad/weird on a lower resolution screens or handheld devices. I'll go with solid, dotted, or dashed.
I agree - it is always going to be difficult to satisfy both old and new, screens, browsers, whatever.
Borders does give a screen-layout a newspaper-like finish. I like.
I actually like the dots. Sometimes when I want a thing to "pop" then I like to use the ridge in a defining color. Otherwise I find that it looks really neat just to have separators that are not too obtrusive. Also I think that not all the dividers need to have borders. Sometimes it's nice just to see it standing in a block without an outline. Where there is an outline however I think the scrolling function is vital particularly with browser differences.