I am having the same problem with photo downloader not remembering previous settings that I have seen discussed here before, except that mine happens for CS5 as well as CS5.1.
I have 2 computers, one with CS5, the other CS5.1, and both have the same problem (as opposed to CS4 where it was fine): I enter my own metadata, change the settings in the downloader dialogue box, and the next time have to do it all over again. I have tried what has been posted elsewhere (create new Bridge CS5 folder in the user library folder etc), and nothing has worked. The file that is supposed to appear in the folder does not (even after several downloads).
If I forget to re-set the dialogue box, I end up without my copyright metadata, and with files downloaded where i don't want them, among other things.
Again, unlike other users, I am having trouble in CS5 as well as CS5.1, but never had problems in CS4.
Any new ideas are welcome. Thanks.