No.
Firefox 1.5x is my primary browser, but occasionally, I have similar issues as you described.
In those cases, I use another browser. For streaming media, if neither FF or Safari work, Opera almost always does.
If it won't play the file within it's own window, Opera 9 still uses the 'old' way of caching internet content - individual files - so sometime I can load a page, then grab the file in question from the Opera cache folder, and play/open it at the finder level instead of through an internet plugin.
Almost always does, because if the problem is the site is streaming a WMV 10/DRM file,
Opera can't 'fix' that - there's nothing (that I am aware of) that will play those on a Mac.