My perception has always been greater bhp for top speed but greater torque for winning 'races'. Power to weight ratio also plays a surprisingly big part as i have found lately.
I am enjoying having the use of two cars at the moment. The first is my run-around Cavalier Turbo which has 204bhp with marginally more torque, 4wd and weighs somewhere near the classic Imprezas 1250kg - doesn't have the chassis though! The second is my girlfriends Clio 172 Cup which has (they say) 172bhp with torque nearer 150lb/ft, Fwd and weighs about the same as a baked bean tin.
Point to point the Clio is brilliant fun and puts a huge smile on your face, i honestly doubt i could keep up with myself driving the Clio if i were driving behind in my last Classic Impreza in 300bhp guise. It is ridiculously fast although being NA doesn't *feel* as quick as the Cavalier which will steam past the Clio at 140mph. In total honesty though the short gearing and torque steer make the Clio a pest to drive for any length of time.
It all comes back to what John says about the power being useable, driver ability and road knowledge. A greater spread of torque will make the car easier to drive fast as this will help dig a driver with less road knowledge out of the hole of not being able to keep the car quite on the boil. To answer your question in my opinion big BHP will make for a fast road car in a straightline. Any other circumstances require the input of so many variables it is nigh on impossible to answer.