Though I am a frequent early adopter of new technology (e.g. Tivo, Treo, etc.) I have not been remotely tempted by the Apple iPhone. This review pithily explains why:

I have a sweet device - a beloved Treo 680, which retailers give away for free after mail-in rebate - and am not about to shell out $600 (with a new contract!) for an Apple WhyPhone without taking it for a lengthy test ride. Fortunately Apple had about a half dozen display models, plenty so that the half dozen prospects in the store could toy around without interruption, while Apple employees circled with questions like, "Ready to buy?"

"No. But I'm ready to report to the world what an unusable keyboard it has." . . .

The real problem is that you can't type a simple e-mail, text message or calendar appointment without suffering the maddening frustration of a carnival game that can't be won, and without getting the screen oily with sweaty thumb dirt. It's the loop toss of data entry — you will never win the big bear.

Update: Several commenters have had a quite different experience.