Since this came up on Twitter, I thought I'd mention two recent purchases: the HP dm1z $400 netbook and the Apple MacBook Air $1000 thing.
In particular, how well do they work with BackTrack Linux?
Both had the same problem common with BackTrack: the boot process didn't work, because the video drivers aren't ready. The MacBook Air goes black, the dm1z goes white (well, not white, but displays random data, which is bright grey).
The solution to this problem is the same. When the grub scene appears that allows you to select a boot option, you press the <TAB> key in order to edit the line. You then add "i915.modeset=0" for the MacBook Air or "radeon.modeset=0" for the dm1z.
This makes the default graphics work, but without acceleration, so some video operations are slow. To fix this, you need to install the correct drivers. I haven't done this for the MacBook yet, but it works easy on the dm1z. You'll want to do it anyway on the dm1z, because you'll want to use the GPU for password cracking.
The only thing that didn't appear to work on the MacBook Air was the built-in BlueTooth drivers. That's to be expected: it's the new BlueTooth 4.0 low power stuff.
The dm1z is more problematic. The WiFi drivers don't work yet, and moreover, it won't allow you to change the built-in WiFi card (boot process stops and complains about unapproved WiFi card). It should work soon though.
The most annoying thing on the dm1z is that the trackpad drivers don't work right. Proper drivers (or maybe configuration) exist somewhere, I just haven't found them yet. It means either bring a mouse with you, or something to press the pad for mouse clicks without causing the capacitance to move the mouse.
The CPU in the dm1z is slow, slightly slower/faster than the Atom depending on the task. But the Radeon graphics on the dm1z are fast -- faster than anything short of a full gaming notebook.
The CPU on the MacBook air is fast (1.6 GHz Sandy Bridge), but it comes with built-in Intel graphics. That should be fine for basic gaming, but it's not a programmable GPU, so useless for password cracking. Graphics performance under Backtrack is slow because I haven't installed the drivers yet, but under Mac OS X, it's really fast. Though, that could be the SSD.
But the 11-inch MacBook Air is impossibly sexy, so I don't know if any review of it matters.
I'll get around to writing a more complete review on these things soon, and exactly how to get them working with BackTrack and doing typical tasks.