I don't see how it's "best" or even "better". Mou, mentioned by others, works better. Mou struggles with large Markdown files, but at least it doesn't have strange display issues when scrolling up and down in the editing window, and it shows more useful visual cues in the editing window.

Currently my workflow for writing blog posts is: iA Writer for the initial draft, then tidy up in Mou, then stick it on swombat.com. LightPaper seems too fragile to fit in that without hassling me along the way.