I often read the satellite forums, so the first thing I thought when I saw your post was "oh no!! here we go again" because the satellite forums have beat this question to death a million times. Take Aquatics advice and check them out yourself. I think you will find that you love some things about each of them and hate some things about each of them as well.
I have had DirecTV since 1995 and have tried both cable and Dish for a couple of months each in the last few years. No matter how you slice it - cable costs more, and most cable providers are still offering analog channels on stations 1-100. I picked up cable for a few months when Comcast fist started doing HD because they weren't charging extra for it while they were testing it out. At the time DirecTV wanted $900 for the box, and only had a couple of stations. They also offered me a monthly discount for having satellite. I figured I would try it for a month or two and switch if I liked it. Within a couple of months, DirecTV offered to send me a HD receiver for $99, so I got rid of Cable because the price was high if I kept it past the trial and I really hated the analog stations.
Dish has good pricing, but be careful and make sure the package you decide on has all of the channels you want. While there base packages are cheaper than DirecTV, they don't include the same channels. I decided to try them out because they had so many HD channels and had a $20 a month discount for switching from DirecTV. I told them I didn't want to sign a contract (you don't have to if you tell them before you sign up that you don't want to. Just make sure you check the correct box when signing your paperwork that the installer brings). I tried it for 3 months. Their service was terrible!! They kept canceling my installation and not telling me (they offered me a free month of service each time). I received an automated phone call telling me that my 3rd appointment was canceled because they didn't have the equipment in stock and they showed up. Then when my free months were up (I ended up with 3) they told me that I wasn't eligible for the $20 a month discount because I didn't send a copy of both sides of my bill with the form. When I pointed out that I did, it was just on two pages, they told me that wouldn't work. I told them to come get their equipment.
I hung on to DirecTV through it all. They have good pricing. I am on an older package that is no longer available, but with most of their channels (except the premiums) and 2 tivos, I am paying around $55 a month. Since I own my HD tivo, I don't pay them for HD and use it to receive over the air HD stations. I will stick with them until someone comes out with a service that will allow me to record in one location on my network and distribute it to any tv within my house. Once that happens, I will be willing to try someone else out. For now, I am staying with the lesser of the evils.
Acropolis