vonage, verizon or time warner?

If you already have cable TV and internet from Time Warner, then it won't cost you much more to get the phone added in with their "Triple Play" package. And this would probably be less than the I think $25 a month Vonage asks for. I could be totally wrong on their rate, though.

Verizon likely has the best service, but will cost you much more. I just switched from having Verizon phone and dsl with TW "basic" cable (like 10 channels) to TW phone, internet, and full cable for a savings of about $10 a month.

The only issue with having TW phone (or Vonage for that matter) over Verizon phone is that when the power goes out, your phone will go out, too. But how often does that happen?

Have you called at&t and complained? They may be able to tweak your set

Sprint offers a device for use in the home which improves in-home cell phone reception. It costs about $130, but if you complain that you have frequent dropped calls at home they'll give it to you for free (except, of course, for the usual 2-year contract extension).

I do not know whether it works only with Sprint or other CDMA phones. You should find out before you try to buy one (since ATT phones work on a completely different principle).