Intel Integrated Graphics
Intel Graphic Media Accelerators (or GMA) are integrated GPUs commonly found on Intel-based motherboards. Their performance, and their driver support in x.org, have been improving at a steady pace for several years now; as of 2008, Intel's drivers are open-source, and are generally agreed upon to be excellent in quality and well maintained by Intel, who are now one of the most significant corporate contributors to x.org.
Because of their well-maintained, open drivers, and presumably because of low power consumption (compared to discrete GPUs on PCIe cards) and adequate performance, Intel GMAs would seem to be an excellent choice for a mythtv frontend; unfortunately, little is known about how well they actually work.
If you have any experience with these GPUs and mythtv frontends, please post it here so others can benefit from your experience!
Known Issues with MythTV
Intel GMA Feature Matrix