Was there anything you did as far as negotiating the salary at the new job or did they offer you that much straight up?
I was going from a really low-paid games job to doing application programming for a large startup. Game programming tends to have even more depressed starting salaries than usual, although this was back when everyone was still salaried.
My former boss actually predicted that I "could make twice as much somewhere else" when I left, and the new employer in fact offered that straight up.