Had the pleasure of seeing both and I'm not answering the poll since as far as I'm concerned they were actually quite different players. Coop was a hug the touchline winger. Which isn't to say that he couldn't cut inside and cause havoc. But, in my opinion he was basically an old school winger. A very very good one though, and probably one of the last of the twinkle-toed generation of wingers who could beat a man by tying him in knots.
Laudrup could play anywhere across the front line, was a bit more direct and pacier. I'm sure he was over six foot tall too. A strong, pacy and very skilful athlete.
If someone put a gun to my head and I could only pick one of them for my team though then it would be Laudrup every time. More consistently dangerous than Davie was. In fact I think Laudrup is the best player I've seen in a Rangers shirt.