Good file downloading program?

I used to use Ares, until it crashed my PC. Now I have LimeWire and Blubster, but my friend who had his PC checked after it crashed was told to get rid of Blubster because it gave his PC a major virus. So Ares and Blubster are out of the picture. Does anyone know if LimeWire is an okay file-sharing program, or should I get rid of it? And.....what IS a good, free file-sharing program??