Marrakech is a very nice city. I was there some years ago. I liked it very much and there are a lot of nice things to see there. It's a very interesting and diffirent city. Here are the best things to see in Marakech in my oppinion:

Majorelle Garden

Jemaa El Fnaa

Bahia Palace

Ben Youssef Medersa

Dar Si Said

Bahia Palace

 

When I was in Marrakech I went on a day trip to the desert town "Ait Ben Haddou". It was amazing! Here they have filmed many movies which takes place in the desert. Among the films which has been filmed here is "Gladiator" (just outside Ait Ben Haddou) but they tired down the place after making the move. I really recommend a day trip to this city.