All In Wonder cards are great for gaming--just as great as the chips they're based on. The AIW X800XTX for example was just as fast as the standard X800XTX, but cheaper due to lower demand. The decreased demand was likely due to people like you telling others that AIW is not for gaming.
I have an AIW X1900...ATI doesn't make a Radeon X1900. It's faster than a Radeon X1800XL.
The MMC thing, well, ATI really screwed up when making its drivers compatible with Windows Media Center. They decided to put the audio through the bus, rather than through a sound card cable, but the result was unsolvable timing issues.
The AIW 2006 is crap for gaming because it's based on either the 9600SE or X1300, depending on whether you get an AGP or PCI-E version. Both the 9600SE and X1300 are crap for gaming.
The last All-In-Wonder that could be hacked-back to earlier TV tuner/audio drivers was the X800XT AGP.
If you're running Windows Media Center, you can skip the problems the new drivers have caused MMC by not using MMC.