If you're shopping for new iMac or MacBook Air, it's probably in your best interest to hold off for a few weeks. Current iMac supplies are very constrained and according to 9to5 Mac's sources, Apple stopped shipping iMacs to resellers this week. With the old stock depleting, Apple is supposedly gearing up to unleash a revamped iMac next week, presumably on May 3 as the company tends to favor Tuesday launches.
Lending further credence to that timeframe, a 9to5 Mac reader claims the shipment of his recent iMac order was delayed until "on or before" May 2. Meanwhile, the folks at MacRumors have heard that Apple plans to update the promo material in its retail stores for next Tuesday. The late April, early May iMac refresh has been rumored since late March when CNET's Brian Tong received word from unnamed sources.
Although a new MacBook Air is also rumored to be in the pipeline, most sources seem to agree that updated 11.6 and 13.3-inch units won't enter mass production until late May with a launch expected sometime in June. Nonetheless, it should be worth the wait as Apple is expected to add Thunderbolt connectivity along with Intel's Sandy Bridge processors, which offer more power and efficiency than the Core 2 Do.