If you are staying in Tangier or passing by on your way to somewhere else, I would definitely suggest stopping in Asilah. I went here one afternoon, while on my way back from Tangier and I just loved it. Asilah is a small fishing village and there is a very relaxing atmosphere. There are many seafood restaurants with fresh fish daily. You’ll find little markets and blue walls (that are made famous by Chefchoen). You will have great photo opportunities in this sleepy Moroccan town. A rare find as most places in Morocco are very busy.
I would also suggest driving the back roads between Tangier and Asilah. We ended up driving along here because we had a flat tire and were looking for a garage. I was pleasantly surprised to find many local artisans who set up shop along the side of the road. As always, in Morocco, there were lots of beautifully handmade goodies to take away at a very reasonable price.
You will enjoy Asilah!