Couple of bugs found in the first 3 hours of using final OS2008 on N800:
-inability to invoke finger keyboard (as noting by Mara and others)
-up button on d-pad does not work when scrolling feeds in RSS reader (Filed at: https://bugs.maemo.org/show_bug.cgi?id=2598)
-thumb keyboard cannot be invoked at all within Skype (even pressing center d-pad)
-moving/resizing desktop applets is frustratingly difficult, and they tend to move around when you put the tablet in your pocket. It would be nice to be able to lock them in place once you have set them exactly as wanted. (Many thanks to the poster who suggested quick movements--that helped, but it is still difficult to get them exactly where you want them)

I'll edit this post if I think of more...

EDIT: I just want to say that, for all the bugs we are reporting, OS2008 is really excellent. It is very attractive, very fast, and so far, pretty stable. Thanks to the Maemo team for all their hard work.