How would one know whether a ticking or tapping sound is a lifter or not.

For example, how does a noisy valve sound.

What else can make a tapping/ticking sound (fairly loud). Keeping in mind that the noise quiets down after about 10 - 20 minutes.

Thanks for the help guys. I'm not going to spend another penny before I'm pretty sure what the noise is. I don't feel like taking the car back to the dealer, as I'm afraid I'll be forced in spending more money without solving the problem.