More importantly than the lack of tactile feedback, touch screens are simply the wrong size. A conventional keyboard is comfortable to write on because the keys are reasonably sized and reasonably spread out. You cannot say that about an iPad, or even about most laptops.
THIS IS SUPPOSED TO BE THE FUTURE! Where is my holographic keyboard? Probably on back-order with my jetpack and flying car. Oh wait, here it is: http://www.thinkgeek.com/product/e722/ They boast of 80wpm.
The letter keys on the iPad are actually very close to the same size and spacing as my full size keyboard. What I find most limiting is the slowdown when switching to numbers/symbols. It's great for plain text, but slower for HTML posts.
