172 every time. Great flaps, two doors, super elevators (shame about the ailerons, but they're no worse than the those on the PA28).
And, it's the safest aeroplane ever, according to the stats. The 172 is a pilot's aeroplane (if you fly it properly - most are landed 3-point despite those lovely elevators.
C'mon guys - do it right and use what Mr Cessna gave you! )
The PA28 has no redeeming features for any airman. They are for transport. Fly one? I'd rather read Poly Toynbee in the Gruniad.
SSD