The Cortex-A8 is pretty spiffy (SIMD extensions, extra compressed instruction mode, ~GHz clockspeeds), but looking down the road, the Cortex-A9 intrigues me. All the same goodies of the A8 but it goes to 4 cores instead of 1.

The other change to look for in the next few years is cheap OLED displays. A 1 watt CPU, bridge chip, and a fractional watt display will change the battery life equation dramatically. Current displays make all the light a display could need to all white all the time and then throw most of it away. OLED displays only make the light you need. Say hello to the '80s and green text on black to stretch your battery for coding.