Paragraph breaks should be intuitive to the content, not because of pixel length.

Write your content accordingly.

You don't think readability has a role to play? Especially on a small screen?

We've all seen content where the block of text is so huge it's easy to lose your place. There has to be a happy middle ground somewhere.

@media blahblah
{
br {display: none;}
}
Just remember to include a blank space before all hard line breaks. Or, in the alternative, taking all risks into consideration,
@media blahblah
{
p {display: inline;}
}

It also seems to be a trend to write 1-2 sentences per paragraph, and sometimes that works; gives the impression of a shorter read, reducing the skimming effect, at least in my personal experience. You see that a lot on sales oriented pages. It depends on the type of content; for in-depth articles, for example, I would prefer longer paragraphs, but I agree that large blocks of text should be avoided as much as possible. I'm not sure how I would translate my preference to lines/pixels, but your current standard sounds good to me, if it's fitting for the content.

With fixed widths I have a troubling tendency to keep editing until all lines fill at least 50%, and preferably 75-90%, of the available width. Coo-coo.

(I say "fixed widths" but I do the same on WebmasterWorld, even though it's responsive and the text will look different for others.)

Think more of the semantics instead of the appearance. A paragraph is as long as it needs to be to complete that presentation of content.

Or set max-width for a little more control.

You don't think readability has a role to play? Especially on a small screen?

I didn't say that. I said write your content accordingly. Think of 'readability' when writing that content. The issue you are seeing is because that wasn't done when you created the content.

But again, paragraphs in content should occur because of natural pauses in language, not because of pixels.

Thanks for the replies.