Yes, despite the fact that Linux is the future, there are companies still producing plugins without a Linux equivalent. The obvious one here is Microsoft's own Windows Media Player. The benefits of running Linux far outweigh any possible downside to not having access to these players, but, as it turns out, you do not have to do without. Consider getting your hands on a copy of the Codeweavers CrossOver Plugin. This marvelous piece of software makes it possible to use native Windows plugins for Quicktime, ShockWave Director, Windows Media Player, and others seamlessly in your favorite Linux browser. For all those movie trailers that seem to be available only in Quicktime format, the CrossOver Plugin is a must, and although this isn't a free product, it is quite inexpensive. Installation is a piece of cake, and you won't need to feel left out when the next blockbuster preview shows up at a Web site near you. Still interested? Here's the address:
Furthermore, some CrossOver plugins can be used externally from your browser as stand alone programs. After installation, these will be made available in your KDE menu.