Answering your questions above:
The HD enabling fee is in addition to the DVR fee, but it's only charged if you DON'T subscribe to Dish's HD channels, which is an additional $20 per month for a package of HD channels in addition to the normal SD channels you receive.
No, plugging your HD antenna into the standard DVR (625) won't work. There's no HD output.
DVR Avtg includes the DVR fee ($6) and locals ($5). Saves a couple dollars a month.
Ok, based on what you're asking, you have 2 options:
You can get the standard dual tuner/dual tv DVR (625) which will output to 2 regular (SD) tvs. This DVR has no HD output to get an hd signal to your HDTV, so you can't hook up your HD antenna or your HDTV. You can probably get the 625 under the dish'n it up promotion for free with rebate. You can keep the same programming package. You'll add a DVR enabling fee ($5.98), and if you do NOT keep it hooked to a phone line, you'll add a $5 access fee. If you DO keep it hooked to a phone line, they will waive the $5. A good deal is the DVR Advantage that includes the programming and the DVR fee and locals, that you were offered above, but it might extend your contract.
If you want to hook up your HDTV or HD antenna, you'll want to ask for the 722 HD DVR, which can output to one HDTV and another SD tv. With the promotion, it should be $99, and you can hook up your HD antenna. You can still use the DVR Advantage package as above (or your current package), and if you want Dish's HD channels, it's another $20 per month on top. If you don't want Dish's HD channels, but you just want to hook up your HD antenna, there is an HD enabling fee of about $6/mo for using an HD DVR but not subscribing to Dish's HD channels. You'll also want to keep it hooked to either a phone line or an ethernet in order to avoid the $5 phone access fee.