decent cable modem

I am going to buy my own external cable modem and stop renting the one I have. I Need to know what to look for as far as selecting a good one. Are there certain specs that it absolutely SHOULD have? Are some faster with line speed than others?? Thanks for any suggestions? Spazzy

I like the motorola surfboard series Cable Modems. They aren't waht I'd call feature packed, but do have a neat usb option.