We've requested the ability to save sort orders in a future version of Expression Media, but for now, that's not a functionality we have. However, there is a relatively easy workaround that will allow you to get back to a search or sort order quickly and easily:

1. Open your catalog, and show the Organize panel.
2. Expand Keywords and click on the Add term + mark
3. Add a keyword to denote your sort order.
4. Hide any files you don't want included, and sort the media items in your chosen order.
5. Drag them all over to the keyword to apply it to the images.

Now, any time you want to get back to the same view, just click the option button next to your keyword. A word of warning, though: if you reorder the images without deslecting the option button, they become a part of that view. Make sure that you clear the option button before moving images around.