I don't know about you, but I'm sitting here on my computer with only two open applications: An Internet browser and my IM client. 90% of the time when I am at home, this is all that I'm using. Sure, my laptop does a lot more. I use it for web development, and a variety of other tasks. But it cost me $1500. There's a lot of work afoot in industry to put out a cheap computer for the masses that can't afford a nice PC, and I just got hooked up by The Raw Feed to this article: Chinese $150 Linux mini-PC races OLPC to market. There's video available (linked in the article) and it's a very intriguing little box. It does more that just IM and Internet, much more. It has Office-like applications, USB 2.0 ports, Linux, video player software, and a cute little OS front-end. It also has a hard drive and SVIDEO-out, things you wouldn't expect in a $150 computer. I could have sworn on the video the man said it had wireless too (although it doesn't have a built-in screen, so you won't be using it at Starbucks).
Intel and Microsoft don't have a lot to worry about, as the device is certainly lacking in a few departments that would make it silly to depend on such a device for 'gotta-work' applications like the office, but this kind of device is going to be able to reach a strata of people that can't afford a PC right now. (Although shipping a non-SVIDEO output mechanism would help hook up to cheaper TV's on the market).
As long as companies that put out machines like this include functionality on the web such as Flash Player and Shockwave player in the base install, I think that they could sell quite a few of these. I think I might even buy one purely as a curiosity, so their market isn't limited to those who can't afford a full-blown computer with all the fixin's.