I remember weighing up either getting the iPhone at the time, the Nexus One, and the Nokia N900. It was a close call between the Nexus and the Nokia, mostly because I wanted those sweet sweet Android apps that everyone had, but ultimately I went with the N900 and it changed my life.
I could write my own Python on the train, I learned C and C++ over the course of a long car trip, and even started writing my own Apps on the device itself. Can you imagine that? On-device app development? In any language you want? It was unheard of at the time, and is relatively unheard of even now.
Those things were awesome. I had an old vehicle that only had an 8 track. My options were to listen to Don't Look Back for the thousandth time or pick one of those up (in the days before ali express) and plug my CD player into it.