Wheels do make a difference. It all depends on the taste, you can fit your 206 with wheels bought from your dealer or you can go with other companies. I'll list a few models here.

The alloys shown below are Peugeot originals:

Phoenix                Hornet                Vulcan                Storm

Nimrod            Hurricane            Tornado

I think the biggest wheel Peugeot dealers provide are 16" (not sure) you'll have to resort to third party alloy manufacturers to obtain other types of wheels.