We're yet to see ARM's Mali 200 GPU show up in commercial devices, but judging from this video demo by NetbookNews filmed at GDC 2010 the smartphone chipset has plenty of promise. Intended for mobile and embedded devices, but here demonstrated on a huge multitouch-touchscreen, ARM's chipset supports OpenGL ES 2.0 acceleration which is put to good use with their home-grown Canvas app.
Video demo after the cut
Canvas isn't intended to preview a UI for a smartphone, of course, but it's designed to demonstrate the shader capability of Mali 200. 720p HD resolution graphics - including 3D renders - are possible, together with physics effects, and all done separately from the core CPU.