I find myself using THIS tool the most. It’s much improved over previous versions, and the interface is pretty and fast.
The whole interface is simple and easy to use. Along the left side are a variety of different filters. Each one expands and collapses. When you expand one of the filter areas, you see a number of different thumbnails. I’ve really become a big fan of looking at thumbnails to decide what I want to do. Now, most of my shots are now bigger 36 megapixel photos, so running any filter (even on a fast computer) can take a while. By a while, I mean about ten seconds. I know I know… ten seconds… big deal… but I guess nowadays we like to see instant results. Anyway, the little thumbnail gives me a really good idea of what the final version will look like, so I end up saving a lot of time.
If you find one you like, you can click the little flag and it goes to your favorites. I recommend this, because otherwise you’ll have trouble remembering if the effect you like was in “Vintage” or “Movie Effects”! I’ve tended to stay in my “Favorites” tab most of the time with occasional forays into the wild for new filters.