As far as I am concerned, a 200 dpi display is not needed, ClearType does its job wonderfully. And, yes, it's cool to take the tablet PC everywhere as a portable book, it makes me feel a bit like a StarTrek character though.
One problem I have with the ClearType tuning tool is that - while it works great for most displays - it doesn't provide enough options for some (maybe weird) displays. I realize the whole thing was done with LCD screens in mind, but it looks great on CRT too.
But on some displays I had the problem that I wanted to increase the anti-aliasing and the general font intensity without bumping up the subpixel rendering at the same time. The result was to either choose a "weak" looking setting OR a "strong" looking setting with color artifacts from subpixel anti-aliasing. Did anyone else have that problem, too?
(On the other hand, maybe I'm nuts and everything is in my head only.)
This is a thing that works great on MacOS and X11 from a readability standpoint, though I believe they don't have that cool RGB-subpixel anti-aliasing at all. And the Windows standard font-anti-aliasing (non-ClearType) just plain sucks (not smooth enough) in case you wondered why I don't use that instead...