Just on the train on my way back from NFS Regent Street. My original N900 was rebooting from day 1, so I've had it replaced. Jon in store couldn't have been more helpful and I've had no more reboots in almost 3 hours of really thrashing this new one, and I do mean *really* thrashing it! I sat in the Maemo lounge for nearly 2 hours before declaring myself happy with the replacement, and I've been playing with it on the tube from Oxford Circus, going in and ou og cellular signal coverage, hopping on to random wifi AP's, etc. Absolutely steady as a rock.

Moral of the tale - if yours isn't working properly, get it replaced!