For a simple answer, for you I might go with Dish if HD movie channels are your top priority. I think most of your other questions are a wash really. This coming from a DirecTV sub since 1996.
1) HD Movies and HD programming (i've been spoiled on hd and can't really stand sd anymore).
Look at the channel lists and compare for yourself on the channels you care about. Right now Dish has more HD movie channels. Then again, Dish has *always* had more movie channels then DirecTV. DirecTV has way more sports. I don't expect this to change a whole lot. As for "regular" HD channels Dish has some that DirecTV doesn't have and DirecTV has some that Dish doesn't have.
I could care less about channel counts. Frankly who has the most changes all the time. It's all about *what channels you care about*. So compare and go with who has the channels you want. But don't be surprised if the other provider leapfrogs with more channels 6 months from now. Just the way it goes.
All depends on who you talk to. However it's pretty well accepted that Dish right now is cutting the resolution on their HD channels to cram as many as they can up there. DirecTV's are at full resolution. If you can tell the difference or not is something only you can answer.
3) Local networks in HD (not sure if this has to be local, just like seeing my fav shows on ABC, NBC, CBS, Fox).
I know it sounds like a broken record but check with each one and see what they offer. Both offer web pages where you can put in your zip code and see.
4) DVR features, record time, and useability
Both are comparable and offer similar thing a different way. Which you prefer will be up to you. Both are good.
5) Ability to "expand" dvr with external harddrive,
Both offer this in different ways, as explained by the other posts above.
also *the ability to export shows off the dvr to my computer for archiving* (via firewire or whatever - I currently due this on time warner's box with a firewire driver - if it can be done, i can figure it out).
Not going to happen due to DRM via HDMI. Assuming the channel isn't protected you can record off the Component outputs, and of course SD is available via composite or Svideo.
6) Price (knowing that I'll likely be getting a full package with every HD channel, special movie channels, dvr's for two tv's (maybe 3), and the playboy channel (is this in HD yet?)
Go to both web sites, plug in what you need and they will tell you the cost. In general if you get the full boat package from both Dish will probably be a little cheaper but watch out for their monthly add-on fees which add up quickly. Again, just do a comparision and you'll get it.