Front Row is a really convenient way to watch movie trailers. You don't have to search around on the web to find the trailers, they are all there in one place in a desktop app, and they play in full screen so you are not looking at some lame tiny window. You can make the movie previews even better in Front Row by watching them in high definition (720p... 1080 is not an option at this time). To see the trailers in high definition, make sure Front Row is closed then open a terminal window and enter the following:

defaults write com.apple.frontrow TrailerBypass http://www.apple.com/trailers/home/xml/current_720p.xml

You can then restart Front Row, and now your trailers will be in 720p. Note that not all trailers are available in high definition. If you want to go back to the normal resolution, you can run the command again but change the 720p to 480p.