aftermarket power supply-Powerbook 17"

Hey all. Looks like my PB power adaptor is finally starting to show some wear. I plugged it in today and the light kept changing from green to amber and the menu tools battery indicator kept changing from "charging" to a percentage, like the connection was being broken. After moving the cable around at the brick end, it seemed to start working fine.

question is, what are the best aftermarket power supplies out there (that are less expensive than Apple's)?

thanks all