Sandy or Ivy?
(Ivy = USB3)
No one knows. They can only speculate, but Sandy would seem kind of pointless as a release candidate next year. Don't get too hopeful on ports for ultra light form factors.
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Stoked. A 15" that is easy to carry at round all day. I called this months ago
I hope it really happens
Current is already easy to carry around all day. You are looking for completely unnoticeable rather than simply easy

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This will be a 15" air...current high performance sandy bridge processors use up 45w.. That's too hot for such a small enclosure..
If the launch window is later, say May, then a thin 'pro' book would've been conceivable, with the release of ivy bridge. But in that timeframe, it's a 15" air, not a pro, or at least a 'pro' that's significantly less powerful than the current pro
Ivy Bridge according to recent articles isn't looking like a truly significant power drop across the board. In a given processor range, it seems like the top tdp used has come down. I think the macbook air is going to eventually occupy the 13" and 15" sizes. The 11" air with 2GB of ram is kind of an awkward replacement to the older macbook.
I think it's too early for the SSD as a standard, honestly. Too expensive, and not all MBP owners would appreciate smaller storage and higher cost. Also, too early for an optical disk killing, especially for high end MBP's.
Ivy Bridge is obvious, and I can speculate a resolution bump up as well. I don't think that the dedicated GPU's will be at all "decent", since when have they really been decent, up-to-standards AND have decent battery life?
With Ivy Bridge, I would expect at LEAST 7-8 hours of battery life with the greatly increased power efficiency. I also believe a design change as well, most likely on the thinning side.
A display upgrade in these would be cool. It's difficult to get quality that thin. I don't think it'll displace the macbook pro. I think we'll see a transition to a 13" and 15" air rather than 11" and 13" over the next couple years. To get the macbook pro into an air like form factor, you'll need much cooler cpus (more than ivy bridge will deliver) and
I think if Apple made a thinner MBP wouldn't they have to remove the optical drive and the HDD? If you take the back off, those two components seem to be the thickest along with the battery (but that would be redesigned). I agree with what your saying about the cost of an SSD, but again, if there is going to be a MBA like MBP, I can't picture it with a HDD.
The GPU was definitely wishful thinking lol. I tried to use as loose of a term as I could.
I think you'll see a 15" macbook air for now. Later on we'll see a macbook pro thinner with integrated graphics. There are many more issues with implementation in a macbook pro including gpu, desire for greater ram, hard drive capacity, display quality, raw cpu power, and ports. We expect greater performance from a macbook pro, and many people use them as desktop replacements. It's pointless releasing a 15" in an air form factor until you have options that are at the very least, not a downgrade in computing power from the previous generation.
That seems like a major possibility, although it's worth noting that due to the flooding in Thailand, HDD supplies are limited and prices have shown a substantial increase in recent weeks. The situation is expected to last until mid-2012. Meanwhile, SSD makers are taking advantage of the situation -- and the expected acceleration in the shift in demand from HDDs to SSDs -- by increasing their own manufacturing capacity (possibly leading to lower SSD prices)
The net result: expect the price gap between the two to become much narrower for many market segments over the next six months.
If I knew it would happen I would have purchased many hard drives before the shortage. The components needed to make ssds are still quite expensive and the margins aren't always that great, so we'll see I guess.
Optical Drives can snap, scratch and become jammed in your slot drive. Your logic is flawed. What is stopping you from getting an external superdrive to burn your irreplaceable storage medium that you might find melted or unreadable in a few year's time.
Archival quality dvds are available. They cost more, but assuming ownership of a device that can read them, they are probably more reliable than archived hard drives. If we had archival quality burnable blu ray media i'd be tempted to use it. Archiving sucks when you have many many terabytes worth of data.