Threaten to leave. Say you can go with Verizon FiOS or TWC (or whatever is available in your area) for whatever your getting now for a cheaper price for the same package. Oh hey! I Googled this and the search returned this: How to Negotiate With Comcast | eHow
I would suggest you call and then say that the bill is too much and if there's any other deal they could do for you, maybe the same as the promotions they offer new customers. That CSR will probably say there's nothing they can do. Or they might low-ball you. Then, tell them you wanna be transferred to cancellation department. That's when the prices will likely drop. The link from Randy was pretty much the same we experienced when Time Warner gave us the run-around. At the end of the day, the cancellation department lowered our bill and locked us in for a decent package.
Is there any other competing carrier in your area? Comcast is in the five worst ISPs in the United States, along with my own, Charter Communications. The telecommunications industry ranks dead last in customer satisfaction, by a margin of over three standard deviations. (No plagiarism, I'm just super lazy right now. Mark Taylor of Level 3 Communications said it. Just Google my paraphrasing.)
We have WOW, but their channel lineup sucks. I live in a condo, so I can't do Dish and DirectTV. By the way, if you have Comcast, Here TV on Demand has a free preview until Monday.
There's an article recently published on negotiating with comcast, written with input from a Comcast insider. Basically, when you say you're going to disconnect, you're immediately sent to a "retention" rep who tries to get you to stay. They get commission if they are able to get you to stay without giving a discount, and they are only allowed to give away so many discounts per (some period... monthly maybe?). It is entirely within the capacity of the rep to give you a promotional deal, but they'll lie and tell you they can't. The article recommends if you don't get a good response with the first rep, call back a few days later and ask for another one. Also, get the rates for Dish and DirectTV, even if they aren't available to you... Comcast won't necessarily know that. They will, however, know which other broadband providers, if any, are in your area, and what their rates are. They will never offer you a deal better than anyone else is offering, but might offer you a matching deal. I played the game with them for about 5 years and never paid more than $35 for Internet (I don't have TV or phone with them). When my 9th or 10th promotional deal offered, they refused to give me a good rate, so I dumped them and went with Clear.com (now part of Sprint.) Clear isn't quite as fast, but their rates are way cheaper, they aren't shady, their services doesn't suck ass and go out twice a week, and their customer service is actually competent. I don't know if they're offering TV services, but you might look into it. Comcast is the most evil, shady, crappy, greedy company I've run into. They've won the "Golden Poo" award from Consumerist (a part of Consumer Reports) for 2 years running. (there's actually a trophy containing a golden poo on a red velvet pillow that recipients receive.) This award is given to the company with the absolutely worst customer satisfaction ratings as voted by Consumerist readers, and actually means something... it means the company simply doesn't give a crap.
Comcrap sucks, and they've sucked for decades. Yes, even before they started with the rate hikes. Charter is even worse. In my local area, they've decided that they're going to force you to pay another $17 a month is what I think it is to have their box, and you can't have cable without the box. This was because they got sick of people in apartment complexes and trailer parks stealing cable. The one thing I want to stress is to be nice to the Comcrap customer service rep, because they have it worse than you do. After all, they work for Comcrap.
Yeah, we don't have Charter in metro Detroit. I have heard the horror stories from my friend who lived in K-Zoo though. I hear you on the working for Comcrap deal. I worked in a call center for the three letter power company for 4 1/2 years. I am always nice, even to the outbound auto-dialers. I know how it is and how bad the job sucks.