In college I worked with a bunch of guys who ended up doing their graduate research at M.I.T. about different touch interfaces. Ended up being pretty good friends (and rooming for about a year) with one of them, and can tell you, (from a lecture he gave), that touch screens may be the next hyped interface, however, there are a number of problems that could potentially derail it.
The first issue is the issue of comfort. From what I gathered from him, most people were willing to use touchscreens for novelty things (ie phones and organizers) but not so much for everyday computing. Simply put, people have become so accustomed to mouse and keyboard type of peripherals that it's going to take a long time to phase out.
The second issue is that the technology is still so young that designers aren't even sure that a touch-style interface would be self-sufficient for applications like typing. Sure we can recognize handwriting, however people seem to perfer the act of typing to that of writing for whatever reason. I personally think touchscreen consoles may become a reality, but much of the functionality we get nowadays I can't see working as efficiently without the modern peripherals.