The D90 is Nikon's new digital SLR aimed at advanced amateurs. It features a tough aluminium-alloy body, live view, high-speed shooting up to 4.5 frames per second, and ISO range topping out at 3200. It's headline feature, though, is 720p HD movie recording. It's one of only two DSLRs currently available that can shoot video but is that enough to make it a worthwhile buy? Cliff investigates.