Out of interest, how easy is it for a reasonably intelligent but not particularly computer savvy individual to get to grips with Linux?
For a (l)user, exceedingly easy. Break them in with Thunderbird, Firefox and Open Office on Windows and there should be only a few contusions (theirs, naturally) as collateral damage when you switch. As the owner of the box, it is straightforward in the same way as these unfortunate people who learned to drive on automatic cars and had to make the jump to a proper transmission. You just need to put in some time and thought. Is the latter such a bad thing? What do you think of people who can only drive automatics?
As Mac has vociferously argued, why on Earth you'd pay for something which will make life harder, make you spend more money than you have already done to go about your business, and tie you in a relationship you will learn to abhor, is nuts.
Keep an XP kernel running - that's what I am writing from right now - but with partitions or spare drives you can have the best of both worlds.
BOFH