And as much as I'd love the Zephyr to Premium, Premium to Core price tag I don't see MS doing that. Pretty much it's possible for them to have 3 SKUs: Core 300, Premium 400, Zephyr 479.99
If you think that's going to happen, you believe Microsoft is incredibly stupid, which I don't.
Here are the facts that we (and Microsoft) know:
1. Console buyers are incredibly price-sensitive.
2. Electronics costs go down over time.
3. Hard drive costs don't go down over time, but capacities go up.
Based on those facts, you'd expect several things to happen:
1. The 360, in all its incarnations to get cheaper, as fast as economically feasible for Microsoft.
2. Models with hard drives to get bigger hard drives over time, as the price difference between a 20GB and 60GB (or whatever) drive evaporates.
3. A model without a hard drive to continue to exist, so that Microsoft can hit the lucrative $99/$129 sorts of price points eventually. (Microsoft's already taken the pain hit for having a non-mandatory hard drive so that they can get this payoff years from now; to suggest that they'd discontinue the Core after taking the hit but without getting the payoff is crazy.)
So I'd fully expect to see "Zephyr", by which I mean a 360 with a bigger hard drive and maybe HDMI, for $299 or $349, with a Core for $199/$249 in the short term.