We bought our daughter, then 3, a play kitchen. It makes a frying sound and the element lights up when you turn it on. The faucet makes a running water sound when you turn the knob, and the microwave beeps when you push the buttons.
My oldest is now 8. All three of my girls LOVE it, they're always making us lunch and dinner. All of our friends and family keep giving them plastic foods, dishes, appliances... the girls squeal with delight everytime they open such gifts! But the other things they get, no matter how cool, are gushed over, but more for the gift-givers sake than they're own excitement.
I love my girls so much!

But I really think that this is a personal question that you'll find out, not one you can gauge future playtime on. All kids are different.. but that said it might be a fairly decent guideline.