Hi,
I think each cat reacts differently to carpet. I had carpet in half the apartment and laminate flooring in the other half when I first brought my 2 girls home. They didn't mind the laminate flooring but it did slow them down a bit with their racing sessions chasing each other and did cause them to slide into walls a bit which was worrying. The problem was that over a few months, they shedded the outer 2 inches of the carpet - all round the house. Now we're in a new bigger house, they haven't really bothered too much with the carpet shedding but I though it would be worth mentioning there's always the possibility your carpet may not stay perfect - as long as you don't mind that.
There's pro's and con's to both and I'd agree with Kaz - get what you want and they'll adapt. It sounds like you already have carpet so you could just wait and see what happens. If they start destroying the carpet or spraying on it, you could always then switch to hard flooring.
Good luck
Nic