The new 12-inch. The perfect form factor (for me), 1.5GHz, standard 512MB RAM (pity it’s 256MB on board and 256MB in slot, so we have a chicken rib), sudden motion sensor (like X40!), new trackpad (two fingers scrolling), and cheaper.
I’ll probably get one after the CNY, when cash flow is back to normal. Bearing in mind that the latest iLife/iDVD can finally create DVDs to a file for burning on another computer, the combo drive version is quite adequate for my purposes.