things to ponder
I'm a very new user, bought a Kindle Touch recently, so here are some comments from a newbie:
My experience is that the Touch has a very nice display. If light is not a problem for you, then you should have no problem reading with the Touch.
As it turns out, I'm using my Touch to read pdf articles, and hardly ever read a book these days. You can read a pdf with the Touch on the latest firmware. This is the reason why I bought the Touch. However, I find I need to select the darkest font, which needs to be reset for each article I read.
If you would read pdf, it'll be worth getting a Touch or higher.
The most disappointing thing to me about the Kindle Touch, but this may apply to other Kindles, is that managing collections is not efficient at all. After a discussion on mobileread, I reached the conclusion that you need to jailbreak the thing to manage collections efficiently.
You sound like someone with little time to waste, so Kindle Touch would probably give you a better "keyboard" experience. I have no problem with the "touch" of it. I do find the menus poorly designed, but that I think is a problem with the software that probably affects other Kindles too. I don't think you'll find the Touch more convenient in this respect, but you won't hurt your fingers pressing on keys, it's smooth.