When my bro and I went shopping last year for a computer, we were blown away by the feature-set of the Acer Aspire One. 100+gb hard drive, 1 gb of RAM, a very good webcam, a nice sized keyboard, multiple SD card slots, and the kicker... Windows XP. It ran XP, which means he could install old games, and they would work. He could install Office if he wanted to, and it would work (yes, we know about Star Office, and use it when we can't get MS Office, but it isn't quite the same).
We were sold, and he is very very happy with it. When he upgraded to Windows 7 beta, he was even more happy with it. He gave the Linux version a shot, but just didn't like it.
If it had better battery life, and a writable screen, and sold for under 500 with a Windows OS, I would be all over it. I would ditch my TX2500Z in a heartbeat. But until that happens, my bro is sticking with his x86 based netbook, and I with my x64 based tablet.
ARM without a mainstream OS is little more than a gimmick, much like Apple OS was before they switched over to Intel, which allowed XP/Vista to be installed in a pinch, and made it a viable competitor to other computer manufacturers.