While we're on the topic of lists, another list that caught my eye recently was Nigel Powell's 10 serious problems with touchscreens that you should know before 29th June (via TUAW). While Nigel doesn't claim to have ever held an iPhone, he brings up some good points about the downside of using a touchscreen interface (ala iPhone.)
Some of his problems with touchscreens include: sun glare (MacBook users are already intimate with this one), grease, lack of one-handed operation and the potential for trapped dirt.
As an avowed QWERTY guy I seriously dig the hardware keyboard on my palmOne Treo 700p. Granted, it took some getting used to, but I can practically touch type on my Treo these days. My wife uses a Sidekick 3 and I swear that she can type on it as fast as a regular keyboard.
I have to admit to having some serious trepidations about the iPhone's upcoming all-touchscreen interface and Powell's piece isn't helping!