Although impressive when working well, media sharing with Windows Media Player 11 is unreliable. It can prove very tricky to set it up to work with an Xbox 360, and other non-Microsoft hardware can be just as tricky.
A very popular alternative is TVersity. Available from TVersity.com, this free application manages your media sharing from your PC, allowing you to view video, listen to audio and check photos, podcasts, standard RSS feeds and more from the comfort of your living room. Configurable with games consoles, some set-top boxes, mobile devices and a range of home theater devices, TVersity is easy to setup, simple to use, and allows you to view all popular video formats.
TVersity also comes as a paid "Pro" version that adds premium online content into the mix - US users can access video from Hulu while UK users can view BBC iPlayer content. ESPN, MTV, E Online, Comedy Central, Marvel, VH1 and many others are also available, with more planned.