If your Adobe CS3 Apps are acting very, very slowly, you could be suffering from a bloated Media Browser preferences file.
That file does cause problems, especially when working from complex file system hierarchies on network shares.
There's a forum thread about it here:
The solution to trash that prefs file seems fine, but it is a pain to do it all the time. Here's a script that installs and activates a background process that deletes the file for you every 30 minutes.