I got all excited reading through this thread because I've had the persistent "Low disk space" problem and second OTA update not installing problem that nobody can seem to fix, then realized that my phone is out of warranty because I've had it for more than a year and I do not have the total equipment coverage. Bummer for me.
I was in the same boat and didn't qualify for the weekend special (free dinc2 with new 2-yr contract).
I just spent 2 days learning to root my phone with the help of a particular GENIUS here in the forums (and input/help from a couple of others, as well) and it's a success. I'm a middle-aged married lady, could be gramma to some of you and I was able to do it with the right help.
I now have a rooted dinc with the latest gingerbread and it's working great.
My next task is to fix the Low On Space issue. You must be rooted to do it, and it's much easier if you haven't yet upgraded to gingerbread.
I'd say read the "
Teaching Gramma to root her incredible" thread in All Things Root (Incredible) forum and see if you could follow it, I bet you could.
The update not installing may have done you a favor.
BTW that happened to me too, after rooting, so I went in and deleted/moved what I could until I freed up enough space, then it installed just fine.
I can't wait to tackle the Low On Space issue, that's next up.