Provided it does allow both the actual HTML markup as well as the "automatic" paragraph formatting if HTML *wasn't* otherwise being used, I would certainly vote for it.

What I wouldn't want is for it to add extra paragraph marks when I'd already used <p> marks, but then I'd also used return to format my post so *I* could read it as I was typing. (ick, a bit convoluted, hopefully you understand what I'm getting at)

-Scott