I would wait to see what happens. There are rumors that Sony is abandoning the Reader (at least in the USA). There are rumors about the opposite, etc.
I'm so appalled by the lack of support (I still can't find the unlighted cover) that if I were hunting a new device I would consider other options and/or wait awhile. Of course, one needs to set a limit or one would never buy anything
And don't misunderstand me. The PRS650 is a fine piece. I've seen the PRS600 and its screen is not match to the pearl screen. And the kindle 3 built looks cheap when compared with the 650. And finally, I should admit that I'm very happy with my 650