First, I'm glad to have made numerous contributions (mostly questions that were answered by wabxjo and others!) to this amazing thread.
Second, my unit is WORKING!!!!!!!!!
I got everything dubbed, leaving commercials in the last two shows that just would not cooperate, deleted everything off the HDD, went through the reset as described earlier, and recorded, edited and dubbed several football games. Works great! No problems at all! No red circles with a slash through it on Scene Delete!
Now, I haven't taped any 30-minute, back-to-back shows yet, but I will soon. But I haven't seen any buggy behavior at all in the past three days. I'm very encourage. So encouraged, in fact, that I went to Wal-Mart and picked up my third 3575. If that's not an endorsement, I don't know what is!
I'm so reformed that I'm dubbing shows as soon as possible, keeping the HDD empty if possible. It's pretty easy right now since I'm off work for the holidays. We'll see what happens when real life kicks back in. After what I went through, I think I will be reformed permanently!
This is only my second brand of DVD recorder. I bought a Sanyo about four years ago, and it was/is horrible. I still use it as an emergency backup (when there are 3-4 football games on at the same time), but it's just not nearly as easy to use. The menus are horrid, the features are poor, it's just not a great unit. Though it still works, so I shouldn't complain too much. But I'm really impressed with the Philips' unit. I have used my two for dozens and dozens of shows over the past three months, and other than me messing things up by filling up the HDD, they've worked beautifully. Sure, there are a few things I'd change if I could, but overall, it's a great machine. Thanks, Philips!
And I'd like to thank wabxjo for providing SO MUCH help to me and many others. Much better, more insightful support than I got from the FAQ-readers at Philips (who generally did try to help and I didn't have to sit on hold at all, so kudos to them). I'd also like to thank my parents, the Academy, and my fans, without whom none of this would be possible.