The MacBook Is Dead. Long Live The (New) MacBook Air.

“At this point, I’m thinking Apple should just replace the standard MacBook with the Air.”

Yes, I just quoted myself. But I have a good reason. I wrote that on October 21 of last year, after one day of playing with the just-released new MacBook Air. Today, 9 months later, Apple is listening. The MacBook is dead. Long live the MacBook Air.

The fact of the matter is that this was inevitable. The MacBook started at $999. The MacBook Air started at $999. I just couldn’t see who would choose the MacBook over the Air. Unless you wanted an optical drive — but the optical disc had just been killed. As I wrote in my full review of the Air a few days later, it even replaced my brand-new MacBook Pro as my main computer. It was that good. And today, it gets even better.

Apple is revamping the MacBook Air lineup, upgrading the device with the new Thunderbolt port, new Intel Core i5 chips, and yes, even a backlit keyboard — finally. The new systems will also be the first built from the ground up to run the new OS X Lion operating system, which is also launching today.

I’ve had the chance to use one of the new systems for the past few days, and it screams. Even the people who thought I was crazy last year to replace my MacBook Pro with the Air may have second thoughts now. Apple is saying the updated devices offer roughly twice the performance of their predecessors in various regular use cases (technically, the 11-inch models should be about 2.5 times faster, while the 13-inch models should be just under 2 times faster). All I know is what I see — it’s really fast and it handles OS X Lion extremely well.

The model I’ve been testing out is a 13.3-inch 1.7GHz dual-core Intel Core i5. It also has an Intel HD Graphics 3000 chip with 384MB of video memory, and a hefty 256GB Flash storage drive. This is the top-of-the-line stock model. But there will also be an option to swap in a 1.8GHz dual-core Intel Core i7 chip (which has 4MB of L3 cache instead of 3MB).

Everything I loved about the last iteration of the Air holds true here as well. The battery life is excellent. Apple says the 13-inch model should last 7 hours during regular web usage, I’ve been seeing just shy of that after heavy usage. (The 11-inch model is said to get the same 5-hour battery life as the previous iteration.) Thanks to the Flash storage drive, the machine boots up in roughly 12 seconds. And it awakens from sleep instantly. Standby mode is still up to 30 days with this battery.

I have not been able to test the Thunderbolt port yet because there simply aren’t enough devices out there on the market yet. But it’s a great addition to have when those peripherals do come. Thunderbolt is 20 times faster than USB 2.0, and it’s even significantly faster than FireWire and USB 3.0. For now, the port works just fine with existing Mini DisplayPort devices.

The dimensions height, width, and depth-wise are the exact same as the last iteration, but the devices are ever-so-slightly heavier. We’re talking 2.96 pounds versus 2.9 ponds for the 13-inch. And 2.38 pounds versus 2.3 pounds for the 11-inch. It’s a difference so small that obviously it’s not noticeable at all.

In fact, the only really noticeable difference externally will be the backlit keyboard at night. This is one feature that many users complained was missing in last year’s revamp. That’s because it was previously available on older Air models, and it was the only MacBook model period without the feature.

Those with sharp eyes will notice that not only is the Thunderbolt port now in the place of the Mini DisplayPort, but also that the keyboard itself is ever-so-slightly different. With the move to OS X Lion, gone are the Expose and Dashboard keys, in their place are two new keys for Mission Control and Launchpad, two new OS X Lion features. To the right of those keys, you’ll also find the backlit keyboard brightness keys on the Air now.

The 13-inch model retains the SD card reader slot, while the 11-inch model still does not have it. Both models have two USB 2.0 ports as well.

With this latest iteration, Apple has also given some extra consideration to the high-end range of the 11-inch models, for users interested in that form factor who want more power. For the first time, there will be an option to get up to 256GB of Flash storage. And it too can be upgraded to the 1.8GHz dual-core Intel Core i7 chip. The higher end of the 11-inch model also now comes with 4GB of RAM standard (the only model that doesn’t is the $999 low-end 11-inch model, which has 2GB).

For the past 9 months, the Air has been the computer I take with me everywhere. I previously didn’t like the Air line because I felt it was underpowered and overpriced — both of those things changed with last year’s revamp. Today’s upgrades should make it even more attractive to would-be purchasers. With just the right combination of portability and power, it is hands-down the best computer I’ve ever owned.

But I recognize that some people do need more power. That’s why Apple still makes the MacBook Pro. But for everyone else, the Air is now the entry-level notebook from Apple. It began outselling the MacBook almost immediately, so this move just made sense. Apple will still sell older MacBooks to K-12 institutions, I’m told. But consumers will no longer be able to buy it.

During their earnings call yesterday, Apple COO Tim Cook noted that two of the reasons why Mac growth was down a bit last quarter (while still up overall) was because consumers were waiting to buy until OS X Lion came out, and because Apple didn’t release a new notebook during the quarter. It looks like they just killed two birds with one stone for next quarter with this device.

The new MacBook Air will be on sale on Apple’s website today, and should be in Apple Stores tomorrow. The price-points will be the same: the two 11-inch models will be $999 and $1199, respectively (the more expensive one has more RAM, more Flash storage, and more video memory). The two 13-inch models will be $1299 and $1599, respectively (the more expensive one has more Flash storage).