If you keep your Current set top box then you will need to get an HD box (which I think goes for about $18 a month), if you replace your existing set top box with an HD box then I think you will only be paying $10 a month HD fee. Your existing TV would work fine with a DTA (typically two are provided free). The swap or pick up HD box is done at the local Comcast office (you can not call that office directly) and hope they have what you need (they mostly do). You will have to either call in or go online to "activate" your new box(s), a process that typically takes a few minutes (you can normally stay on the line and confirm that you are getting the channels), although the downloading of the 'guide' can take several hours.
You can indeed keep your existing setup with your HD TV (getting SD images through the Comcast box(s).
If your new TV has a QAM tuner (almost all do), you can run the Comcast cable directly to it and receive you Limited/Basic (mostly Local) channels, including HD if your local station(s) outputs HD.
you can easily go to your local office and ask for an hd box, the question is will they have one. When you get home call comcast to have it activated. you will also need to pay the 9.99 hd technology fee.
I just purchased a new HDTV, which is scheduled for delivery on Friday. I currently subscribe to Comcast's Digital Starter package (in zipcode 98155).
Our current TV is an SDTV, and as such we've had no need for an HDTV box or signal. If I want to keep my current SDTV box for my old TV, and add a new HDTV box for my new TV, can I just go to my local Comcast office and get one? Or do I have to call in and have it 'activated'? If I call in, what is the general turn around time for getting a new box sent out?
Can I keep my existing Digital Starter package with the new HDTV?