For offices, and for a lot of people's homes, I, for one, can certainly see a merging of the console and pc market. An apple isn't much different anymore, anyway.
What people -want- is a machine they can use for e-mail, games, some office work, showing pictures to friends, and keeping in touch (friendslists, facebook, whatever). You can do all of those except office work with a PS3. You can do all of those (except for some games) on a mac. A pc with windows and whatnot, for the average user, is horribly overcomplicated. They don't -want- to have to look under the hood. Some people want to be able to do more; but those are unfortunately going to be facing the problems Linux users are facing now.
My guess for the future: everyone has a computer/digital tv/console hybrid at home, a severely handicapped pc at work, and some smartphone/netbook/palmpilot hybrid for in between. The regular laptop will, for the most part, disappear - only people who really need to be able to do presentations on the move and such really have a need for them. The home desktop will become more rare - hobbyists and fanatics will still use them, but most people will have migrated long ago.