If for some reason you have to stick w/ comcast check out this modem:
http://www.amazon.com/Motorola-SB6121-SURFboard-DOCSIS-Cable/dp/B004XC6GJ0

Had it for a year so far, already recouped the cost via no rental fee.

As an alternative you could get wireless 4g service from AT&T, Verizon, Clearwire, whatever.
Latency will be higher, as long as you're not too picky it shouldn't piss you off too much.

GL


Edited by thaxor (05/21/13 03:01 AM)