A rather interesting Atom nettop is on sale in Japan, at AKIBA.

Based on a dual-core Atom 330 and Nvidia's Ion chipset, Asrock's ION330 packs 2GB of DDR2, a 320GB hard drive, HDMI, D-sub, S-PDIF and a bunch of USB, making it one of the best equipped Atom netbooks on the market. Thanks to the dual-core CPU and Geforce 9400M, CPU utilization during 1080p playback is just 34 percent.

Unfortunately, the asking price is just over $400, and it's not a bargain by any means. You can put together a pretty nice mATX HTPC for that kind of money, and get quite a bit more CPU muscle and storage.