Say what you like, the Nexus One is a decent smartphone, with a lot to recommend it.
I bought one primarily because it seemed that manufacturers and carriers were "dragging their heels" in delivering Android updates. Don't get me wrong, Android 1.6 and even 1.5 are very good, but I don't see why consumers should be locked into them, simply because of the Motoblur and Sense etc., addons.
Seems to me that the carriers and manufacturers would prefer that the o/s is static for the lifetime of the phone, sparing them the expense of recustomising and rolling out updates. What the Nexus One promised, it delivers: a well-designed and built handset, running "vanilla" Android - it does everything I need it to do, and it represents (to me) value for money.
I don't need the glitz and empty glamour of a customised UI, I'd sooner have a handset that can receive updates in a timely fashion, but each to their own.
I'll keep using the Nexus One until the hardware cannot cope with the latest iteration of Android, using whichever sim-only deal represents best value at the time. When it finally dies or becomes truly redundant, I'll buy the best available sim-free Android phone that gets its updates direct from Google, always assuming that Motorola, Verizon et. al. haven't finally destroyed the platform in a fit of greedy pique.