The temple itself isn't very impressive actually ... It really doesn't consist of much more than that 1 column and a few stones from the foundation ... there's nothing to see beyond that.
However, there is an archeological site nearby where they reconstructed parts of the ancient city of Ephesos. That one is pretty impressive if you like archeological sites ... or if you like cats ... or both.
The virtual reconstruction of the Temple of Artemis looks so good, I can now see why Antipater of Sidon declared it the best of the seven wonders of his time.