I read the above post back in the fall and thought, "yeah yeah, I'm using HttpURLConnection, so need to think about this at all."
Well this week I found some odd, frustrating behavior and decided to try the Apache HTTP Client to see if it gave different results. And oh boy, does it -- it always just works!
OP Jesse says Apache has "fewer bugs" on Froyo, which is my target release. I guess I should have switched sooner. But now I have!