When I picked up the ultra-thin Sony VAIO X this summer, I actually did a double-take; it was so light I had a momentary impression that local gravity had failed. It was so light, when I went to pick it up I ended up jerking it into the air because I'd expected something twice the weight. That was a prototype sample, so I have yet to find out if the shipping model is quite that unfeasibly light in my hands, and I'll need to take it on the road with me to see if it's robust enough for a life of travel- but this is what I expect an Atom netbook to be. It's got an 11" LED screen, and despite being only 13mm thick (including the screen) it has VGA and Ethernet ports and while the keys don't travel very far, the feet underneath (which are mainly there to improve the airflow) also give you a nice typing angle. I'm not normally a fan of 'chiclet' keyboards with widely separated keys but I found I was typing more accurately on this than on the average netbook.
Sandisk dropped me a mail this morning to say they're part of the anti-gravity effect. Their 64GB pSSD weighs 7 grammes. 7 grammes! That's the same as a silver cufflink,an MVS-HF LONG RANGE rocket transmitter,a 2.5mm jack plug or two paperclips (according to a quick Bing search). An egg weighs 50g. While we're at it, a chocolate bar, a bottle of shampoo and a Psion Revo PDA all weigh around 200g, as I remember Stephen Fry noting at the Revo launch. The whole Sony VAIO weighs 13 eggs or as we usually put it, 655g for the very lightest version (presumably with the Sandisk SSD) or 780g if you go for the meatier model with a 256GB Samsung SSD instead (Sandisk tops out at 64GB).
The prototype I was flinging around had a 4 cell battery, which Sony promised 7 or 8 hours from, and weighed 600g (oddly, even with a 128GB SSD). Clip on a slab the size - and probably the weight - of the machine itself and Sony says the 8-cell battery will take you up to 16 or 20 hours on the go.
You pay for the portability; prices are north of £1,200, which is high for an Atom processor. But what you pay for is pretty amazing portability - and when the high end is this light, expect a lot of only-a-bit-heavier models at a more reasonable price. My back thanks you...