Xbox Next (Base Model) @ $249.99 to $299.99 price point released on Nov 11, 2005.
Includes the advanced IBM and ATI processors along with high level sound system to ensure a powerful next-gen system that should allow for even more advanced games than those seen on PC's for ~2 years, at least. Fully HDTV compatible as well. Has hi-capacity expansion (or memory card) slots allowing for portable and accessory storage cards to be purchased for game saves, faster loading, downloads, etc. These memory cards will start out at over 512mb of storage each and retail for approximately $40 to $60. PS2 and Gamecube games, for example, function fully without the use of memory cards, but if you want to save your game or replays, you *have* to have a memory card (less cost of the system but more post-purchase revenue for the manufacturer). Wireless controller support from the get-go is still up in the air, but imo, it should be standard. Xbox Next Base will be very sleek and small universally and will either be black with hints of green or a darker silver with hints of green and black.
Xbox Next HD @ $349.99 to $399.99 price point released on Nov 11, 2005
Inclues all the features of the base model plus a few important extras. Not only does this unit have a memory card expansion slot as well, it will also have a larger built-in storage disc of some sort (5+ gigs I presume). It will probably also include progressive scan DVD support, media extender functionality, and backwards compatibility, hence the higher cost. So, for developers, developing for the Xbox Next won't require any real special customizations for either version since they're both essentially the same, except for those little extras some hardcore fans are pining for. Games will be developed so they can be played without any sort of hard-drive, *but* they will also be made so that if a hard-drive is present, then saving, caching, downloads etc. (at the discretion of the user) will be fully functional. The XBNHD will only be slightly larger than the base unit, if at all. Down the road Microsoft will have the option of releasing an Ipod-like device that fits conveniently in the expansion slot and can be filled with music from the Xbox Next hard drive or from the internet through Microsoft's live service. Movies and TV shows could be possible in the future for download onto portable devices or for viewing on XBN like a tivo service of sorts.
Xbox Next PC @ $649.99 to $899.99 price point released on Nov 11, 2006
This unit will essentially be a media center PC using the latest Microsoft OS and give the user even more options (DVR, PC, downloads of movies, music, etc, internet, communication via videophones, television, etc. or essentially a media center hub!) in addition to having a built-in next-gen gaming console. PC games and other software can easily be installed and used and Microsoft can license out it's OS+ XBN technology to PC manufacturers for them to include this functionality in their media center PC's to create a sort of standard Allard was speaking of (or at least move in that direction). Microsoft would subsidize the cost to manufacturers so, while they still lose on each unit sold, they will be the ones gaining with game and live service royalties. Microsoft has successfully created a dual revenue stream (game royalties and online) that will help them become profitable in the long run, imo. To play Xbox Next, the user would just select that option from the boot screen and then the unit would function just like a regular Xbox Next HD unit. The standard Xbox controller (which would come with the unit as well) would have to be used to play the game. Because of XNA, games could be made to work one way on XBN and then they could also be installed (probably a PC version) on the PC side of things of the XBNPC or on regular stand-alone PC's and played online against (or in conjunction) with Xbox Next players. An Xbox Next game will not be the same as a PC game and it will not work in a PC and vice versa. If there are "ports", they will have to be just like they are now in terms of plug-and-play for the XBN version and installation for the PC version.
I don't think I've hit everything on the mark in terms of what will actually happen, but I think this is the most logical extension of Microsoft's tentative next-gen plans. It will not only allow them to release a mass-market next-gen console for the masses, but it will allow them to release a slightly more featured unit for the hard-core crowd at the same time without really alienating anyone and without having to eat alot of the costs themselves for features some users won't even use or care about. If the consumer is clearly educated on exactly what is being offered (which Microsoft has lots of experience in), then things should go very smoothly. And in Japan, where Microsoft has had it's hardest challenges, the smaller, streamlined unit will go a long way to win over some new customers and you just know Microsoft will learn from their abysmal first outing and come out with many more advanced Japanese-tailored games made by Japanese developers. Add in the slew of high quality western games that XBN is sure to have, and more Japanese gamers may actually consider giving the western console a try this time around.