SMPlayer
SMPlayer is a fully featured video player built using the Qt 4 libraries. It basically plays anything, including DVDs and ISO images, but it skipped the menus when reading DVD ISOs. It's complete and it offers plenty configuration options, including for subtitles and the interface itself, allowing to choose the icon set and the style used. You can also configure the language SMPlayer uses for its interface, including English, Romanian, Polish, German and many other. I was impressed to see translations are pretty much complete.

Kaffeine
This is one of the best KDE video players, currently at version 0.8.6 using Qt 3. Work is in progress for the Qt 4 port too. It plays anything and it handles very well any kind of movie formats. It uses the Xine engine, offering powerful configuration options for it.

More Here