I think it'd be quite difficult to make a living editing from home from the start off as it takes time to build-up a client base. In fact to be honest I think being freelance initially might be a struggle for the same reason. People tend to hire people they've worked with before, and so it might be more prudent to look for a staff position to get you going. But that could help you move into the sector, as the vast majority of staff positions are in the corporate/shortform video sector - and many of these companies now like people who can do a bit of everything, i.e. video, web, flash, graphics etc.
Corporate projects can be fun, as the budgets are a lot higher (in terms of £s per minute of screen time), and they're often quite glossy and flashy end products.
The bad news though is that there's likely to be a contraction in this sector in the short term as companies reign-in their marketing spend.
A Mac and FCP will give you a good set-up for home-based work. But although FCP has made an impact on the market, most professional work is still done on Avid. The FCP training courses are great but they won't get you a job. I don't think many employers would actually know what an Apple Certified User is to be honest. In any case all those exams prove is that you know which buttons to press, they don't prove how creative you are, or how well you can tell a story - and that's more important I reckon. Having said that the official training books are really good and I've got most of them myself, as well as doing a couple of them as tutored courses. (If you're interested in doing courses, contact Northwest Vision & Media - Home page : Northwest Vision and Media - as they can offer 70% training subsidies)
Personally, most of my work in in the broadcast sector. It does tend to pay a slightly better daily freelance rate, plus the projects are longer so it's easier to plan ahead. But really the main reason I prefer longform work is that I like crafting stories, I like starting with a mountain of footage and shitting myself how the hell it's ever going to come together. And it's a bit more of a laid-back environment, being less client-facing.
Moneywise it can be good. Freelance is potentially more lucrative but there's zero security. Last year I made about £***** as a freelancer, but after mid-February I have no work in the diary, (and that's quite typical situation to face.) There's a lot of faith placed in the phone ringing! But then I have no dependents, so the consequences of potentially being skint aren't too severe.
I hope all that makes sense. It's certainly fun a lot of the time, and no duller than any other profession the rest of the time. Feel free to give me a shout if there's anything else you'd like to know.