Like the MacBook and MacBook Pro, the new Nvidia-powered MacBook Air also uses hardware-acceleration for H.264 video playback. Benefit: Performance is better (duh), but also important for people who toasted their kibbles 'n' bits playing video on the old Air, the new one runs dramatically cooler.
One Mac Rumours forum member found that the new Air ran a full 10 degrees cooler playing back the same video, since it apparently dials back the CPU as the GPU picks up the video jujitsu. One wonders just how much it'll help (or hurt) battery life too, if at all. [Mac Rumors]