Fred,
2000 JPEGs!
Are you kidding?I am.
I've used Expressions Media since it was iView MediaPro v1.x for my digital library archive. It was the only program of its kind that provided this function when I bought it. As far as I can tell, Microsoft didn't do anything with it other than add recent digital cameras' raw file compatibility to it. PhaseOne has not done anything with it yet, but my hopes are high.
While Bridge is a sprite program, when its cache get corrupted it brings the program to its knees. While CS4 Bridge is far better than previous versions, cache corruption can still pose a problem. For this reason I prefer Expressions Media.
I don't use the slideshow function for browsing. I set my thumbnails to a large size and can scroll through a library of 10,000 images (raw, PSD, TIFF, etc.) without waiting for anything. Its search function is equal to Bridge as far as I can tell, but I've not used Bridge to search through thousands of images.