What's not included: An Xbox Live headset, an ethernet cable, an HDMI cable, high-def component cables (the Arcade is composite only we're afraid) ... oh, and the full version of the above listed trial games. Though Amazon listed a $279.99 price point, the tipster reports a price more like $299. Now all we need is a press release acknowledging this thing exists so we can double check that price.
[Update: Looks like there's some confusion over whether or not the above games are in fact full games or simply trials. The box lists the five games and says: "Plus Five Trial Games!" Is that "You get the console, the peripherals, plus these five trial games!" or "You get these five full Xbox Live Arcade games plus five totally separate trial games that aren't listed on this box anywhere so as to make this a confusing piece of marketing!"
Your guess is as good as ours (see Microsoft, a press release would've really helped out here) but we're trying to get an answer for you guys. Sit tight.]