Nokia N810

Nokia announced the N810, a Linux tablet similar to the N800, with additional slide out keyboard, built in GPS receiver and car holder for less than 500$.
Update: there seems to be only one SDHC compatible miniSD slot on the N810, compared to two SD slots on the N800. On the other side, there seems to be 2GB built in flash on the motherboard.

Update 2: the Nokia N810 seems to have a transflective screen, so it should be usable in direct sunlight! Finally! This was my main reason not switching from the 770 to the N800, as both have nearly invisible screen, when you are outside in the sun.