You could say that I made the decision based on the advice from this forum---both this thread as well as a number of others that I looked at.
With the estimated repair costs, we checked with some local professional musicians. Without our identifying where the quotes came from, they knew which store had the higher quote, but said that while the shop was more expensive, the quality of the work was superior and it was where they went. While I'm nowhere near professional level, I knew that if I were to repair, I wanted to get it done where I could trust the work and know it was quality--so repairing was going to be expensive.
Simultaneous to this, I tried out all the flutes in the local area in my price range, plus a few over my price range (granted, I'm in an area with only a few stores, but I was still able to try a number of different brands and models). This included taking a few home overnight for more extensive trials. Trying out flutes gave me a sense for what was available, and there were some that really just made me enjoy playing. I would get caught up in the feel and sound of the flute, the joy of the music, and forget that I was supposed to be evaluating the flute.
Ultimately, I wasn't confident that even a great technician could bring my 30-year-old flute (now I'm feeling old!) up to a level equivalent to a new flute. But if I put $900-$1200 into repairs and then wished I had replaced, the repair costs would basically be sunk and would be significant enough that I wouldn't be able to immediately buy a new flute. With a it being potentially only a few hundred dollars more to buy a new flute, that route seemed less of a risk, especially since I liked some of the new flutes I had tried.
Thanks again for all the input. It was very helpful as I worked through what would be best for me.