Just had my cable modem service upgraded from 3Mbps / 256Kbps to 4Mbps / 384Kbps for an extra ten bucks. Running some bandwidth tests I’m not quite seeing the full speed, but it is close. I suspect that for this service level they’re capping the modem at the stated speed instead of their usual +10%.
Speakeasy now can supposedly deliver ADSL at 6Mbps / 768Kbps to my neighborhood for about double what we’re paying now. If it were about $25 cheaper I would be all over it…

Download SGuide and do the register hack
http://www.lostindiantribe.com/Download.html
The site belongs to a senior Cox High Speed Data tech who does a lot of their “problem” installs.
Also, make sure you have the “newer” 2.0 modem that is Docsis 1.1. compatable.
All of the above have gotten my speed over 5megs down and 750 kbps up