My prediction for 2008, PS3 sells like hotcakes in Japan compared to 2007 (360 sales fall flat). 360 and PS3 sales gap will narrow further or overtake for North America, Europe PS3 sales will significantly overtake XBox 360 total sales there.
Christmas 2008, PS3 sales starts to beat global sales of the Wii (have been called names for suggesting this with regard to 360 vs PS3 Christmas 2007 sales last year, now people may be a little more open minded).