I've been a little more active on my blog recently, largely thanks to Red Sweater's MarsEdit (formerly published by Ranchero Software) which enables me to write blog entries in an off-line mode, and then upload them once I've got it finished. It integrates with a few features that a simple text editor doesn't; for a start, I can keep track of different blogs in the same tool, as well as see/edit/delete existing entries in my blog without having to copy'n'paste. It also works with other blogging software tools; of course, I use Blogger.com, which is a whole lot better after it was taken over and given a facelift by Google – but it works with WordPress, Movable Type etc. too.
It also allows keyword/categories to be specified (though not added to at this stage, it seems) which makes it quite handy for categorising blog entries both after and during their publishing.
The key benefit for me is that you can open up a Preview window, which shows what your rendered HTML looks like. I've fought for hours sometimes trying to get tables to display properly, but to no avail; the preview shows how it's going to look before it goes up to the site with HTML errors in.
In addition, the editor can have custom tags – so for example, if I want to type an N dash, I just press Command+Alt+N, and voila – an N dash appears. It also understands smartypants and markdown formats for previewing, if that's your thing.
Lastly, the editor has support for AppleScript, so there's a bunch of extension you can add in. I like the ability to add paragraph marks <p> around the paragraphs, which is helpful if you're not using the break-every-line-with-<br> flows that some editing software loves doing. But if you've got a favoured editor, then you can configure MarsEdit to use that instead.
In all, if you've got a Mac and blog regularly, I'd recommend checking this out. I can't say it's the best one, having not used any others – I'd seen it before but not picked it up since Ranchero didn't accept PayPal; now that Red Sweater are looking after it (and they do accept PayPal), it's worth having a look at. It's got a 30-day free trial if you want to play with it ... I tried it for a couple of days before stumping up the cash.
I'd be interested in hearing others' opinions on this, or other pieces of similar software. Leave a comment after the beep ...