The Sapphire Radeon HD 2600 XT ULTIMATE
As far as the raw hardware specifications go, the Sapphire 2600 XT "ultimate" is functionally identical to the Powercolor version, which runs at the same clocks and provides the same performance. However, the "ultimate" edition comes with a few perks.
First of all, the card is passively cooled, and is therefore completely silent. This is a great feature, especially for video cards used in a home theater PC where silence is paramount.
To further its home-theatre aspirations, the 2600 XT comes with HD component video output in addition to the HDMI option. Many early HDTVs don't have HDMI yet, so this is a plus for folks with this setup. Of course, there is also the DVI-to-HDMI converter, and like its Powercolor cousin the Sapphire, it also comes equipped with a built-in sound processor for the HDMI output.
However, what I really liked was the bundled software and games. Sapphire's Ultimate card comes with PowerDVD 7; a full version of 3dMark 06; and Valve's "Black Box," including the triple bonus of Half Life 2: Episode 2 and Team Fortress 2. (These games are not yet available by the way, but Valve lets you play Day of Defeat in their stead until the release date).
Of course, the ultimate edition will likely cost more than the $100 2600 XTs out there today, but the game bundle is very attractive. Definitely worth looking into the price difference - assuming these 2600 XTs perform up to par. Let's see what the benchmarks have to say about that!