Well, thanks to all for the interesting and informative discussion.

Sadly, I went with digital cable anyway. Reasons:
1. I live in a 1st floor apartment, so no matter how I mount my dish, someone can intentionally or accidentally mess with it, knock it over, etc.
2. I live below one of the model apartments, which means the rental agents and apartment landlords will be walking around my place all the time showing the model to potential renters. I know the law is on my side if I put the dish on my own patio, but I didn't want to have to fight them and have them try to find some convenint "other reason" to evict me.
3. To add all the channels I get on digital cable now (at least the ones I care about) would have actually cost more than my cable service. Factor in adding a 2nd DirecTV box for my other TV, and it just wasn't cost effective.

My next thought is that I might want to get a ReplayTV 4000... I'm going to start another thread to ask for comments from anyone who owns one, rather than have this one split off into another tangent.