+1 on the "What router did you buy" question. I had similar behavior earlier this year on Charter. I went through several cheap routers. My son finally talked me into getting one of the "gaming routers".. Not readily available locally but Amazon has good prices BTW. No problem since.
BTW - don't make the mistake of enabling the router notification options! I tried that and had my email account promptly disabled by charter. Turns out the router was getting hammered with intrusion attempts and the cheap'o processors couldn't keep up. Charter's response.. "it happens nothing we can do".
I'm really wondering if U-verse will be better?