Ah, I got a new cable modem today and am finally taking full advantage of my cable internet. I don't think 14 mbps down is too bad considering its "just" cable:
Before with the D-Link modem I was peaking at about 6mbps down and 600kbps up (DOCSIS 1.0). This Motorola modem is compatible with the DOCSIS 1.1 protocol Comcast uses out here, and goes much faster