Now. Unless an update is imminent or the current model is out of date, my suggestion is usually by when you need one. There is very little chatter about an IP3 or HD. Yes, there were lots of rumors earlier but not as much now. No new cases or prototypes being proffered -- the typical stuff you get when a product is coming soon. Also, the IP2 is not old in the tooth in anyway. It's still the best of show of all the tablets. Heck my, IP1 is still the quickest computing device I own and I'm still completely satisfied with it. Since there is a media event early Sept, maybe wait until then. Maybe.