I broke down and bought a Nexus One last week.
I got the original G1 phone from google when it came out, and I hardly ever used it. Why? I generally hate phones - they are irritating and disturb you as you work or read or whatever - and a cellphone to me is just an opportunity to be irritated wherever you are. Which is not a good thing.
At the same time I love the concept of having a phone that runs Linux, and I've had a number of them over the years (in addition to the G1, I had one of the early China-only Motorola Linux phones) etc. But my hatred of phones ends up resulting in me not really ever using them. The G1, for example, ended up being mostly used for playing Galaga and Solitaire on long flights, since I had almost no reason to carry it with me except when traveling.
But I have to admit, the Nexus One is a winner. I wasn't enthusiastic about buying a phone on the internet sight unseen, but the day it was reported that it finally had the pinch-to-zoom thing enabled, I decided to take the plunge. I've wanted to have a GPS unit for my car anyway, and I thought that google navigation might finally make a phone useful.
And it does. What a difference! I no longer feel like I'm dragging a phone with me "just in case" I would need to get in touch with somebody - now I'm having a useful (and admittedly pretty good-looking) gadget instead. The fact that you can use it as a phone too is kind of secondary.