Thanks so much for your advice, everyone! In the end, I've gone with a Wordpress.org package from Bluehost. I got the domain, hosting, emails, etc. The decision to go for WP.org was inspired by the SoW webinar by Bad Redhead Media*. I'm getting on alright with it so far. Bluehost offers some great support resources.
@Danny - The advice in some of the books I've read seems to be that it's handy to have a website, even early on. Perhaps it's not a necessity, but I fancied taking a look at how to do it. I'm finding it quite a fun thing to whittle away at when I'm not writing or at work. Perhaps it depends on how you're planning to use it.**
*I recommend the Bad Redhead Media Marketing Challenge book. It makes a lot of unknown and initially vaguely terrifying concepts clear and easier to approach!
**Also recommend Jericho's resources about websites and mailing lists.