Disclaimer: I haven't gotten my hands on one of the new MacBooks or MacBook Pros yet. I may not have time to for a while yet. This take is based entirely on published specs and reviews, along with the announcement info.
First - the price-reduced MacBook (plastic) for $999. It's simply a re-pricing of yesterday's $1099 model, but breaking the psychological $1000 barrier is important. This holds the line short-term until the first serious price cut on the new MacBook models.
Second - the new MacBook. I love that we've picked up some Pro features, like the multitouch trackpad and discrete VRAM. I also like the speed and the fact that it uses the same high-end chipset as the Pro. My one quibble is that Apple has eliminated the FireWire port (goodbye, Target Disk mode) without giving any sort of reasonable substitute. USB takes care of virtually every serious need but migration and troubleshooting are a lot harder without the FireWire port. And that also dictates that despite the greatly improved specs, there will be no use of this at all in the DV marketplace. Pity. Otherwise excellent.
Third - new MacBook Pro. The 17" model is essentially dead (it did not get changed at all - no redesign), so we'll skip it. The new specs are truly splendid. Still 4GB RAM supported (that won't change in laptops for a while yet), but cache is improved, bus speed is faster, they now use DDR3 RAM, bigger drives are standard, and coolest (though the software limits the coolness at the moment) is the fact that you can run on either the lower-power integrated graphics or the swank-ass dedicated GPU. Real neat. I also like that we don't have latch mechanisms anymore, and easy access to the hard drive (along with the DVD slot moving to the side).
This space efficiency comes at the cost of the FireWire 400 port (there's still a FireWire 800 port, but I'm wondering if the clock is ticking for the interface), and DVI has been replaced by DisplayPort. That has great long-term potential but right now it means you'll need a dongle to use pretty much anything but about 5 TVs and the new Apple Cinema Display 24" that ships in November (which also dumps FireWire, but adds a MagSafe plug so no more having to buy a separate adapter for work - yay!).
I like the new look of both, too. Pretty spiffy. I miss matte displays but I don't hate glossy the way some do. Personal taste.
Fourth, and finally, the MacBook Air. Meh. It got the new chipset (good - it should improve speed and battery life a little), DisplayPort (OK), and a bigger hard drive (120GB is usable, and the new 128GB SSD option is even better, if pricey). Still the same clock speeds, and still only 2GB of RAM.
Maybe the next update will give it some love (speeds of 2GHZ or more, and 4GB RAM installed, along with either a wired Ethernet port or another USB port). By then the HD should be up to 160 or maybe even 240GB.
I don't expect to own one of these new MacBook Pros anytime real soon (unless I either have an older machine die or hire someone else), but the good news for me is that if/when I do at least I'll be able to use my Apple discount. Makes it a little more palatable. I will be installing quite a few of them in the next few weeks, though - they are a truly nice ride...