looking at the power and torque graph, it is true that the 16v can have slighly less torque than the 8v at certain engine speeds but in reality, on a well run-in example it is barely noticeable and as everyone has said, hit 4000rpm and the 16v takes off like an 8v never will.
I always used to run out of puff in an 8v when overtaking but haven't yet in a 16v.
However the MPG of a 16v is around 30 whilst an 8v will be around 38. Quite a difference if you do miles. Also the 16v is a fair bit more complex so with high miles/small budget I'd go for an 8v.
If you drive on the kind of roads where you can make full use of the 16v's top end then buy one. Or if you live within the M25 get an 8v

Let's face it, both will be a good choice.
Cheers