I switched from a Sony Ericson T68 to a Nokia 7210. The main reason being that the T68 was slow and unresponsive, I'd liken its pace to a Lada estate in the slow lane, on a Sunday.
It also kept switching itself off when I was using it.
The 7210 is a great phone, it has java games, a reasonable WAP setup and a radio.
Switched from a Samsung SPH8500 to a Samsung N400. Gotta love playing the actual arcade version of Ms. PacMan. I am now considering a SERIOUS upgrade to the Samsung SPH-I500