DON`T GO IN THE CENTER WITH YOUR CAR BECAUSE YOU WILL NEVER REACHES THE NICE THINGS.
Fun Alternatives: There is a nice way to avoid all the parking problems, there are a few beautiful parking garages where you can park for reasonable prices.
It is a beautiful town square, but with nothing but souvenir shops surrounding the square, I must say that this is a tourist trap. Each store is pretty much the same as the other. If you want to get the obligatory tee-shirt or things with delftware design this is the place to be.
Unique Suggestions: Go inside Nieuwe Kerk and if you can climb up the tower.
Fun Alternatives: If you want real Delft gifts, try any of the stores outside of the main square.
Be careful if you are hungry or want to buy a souvenir at one of the shops at the market place. Especially the reastaurants are tourist oriented and more expensive than others.
Fun Alternatives: Try restaurants and cafés away from the market place and compare the prices of the shops. If you are on a budget trip, go shopping in the shopping center near Zuiderstraat.