Rabat

View of the Bou Regreg River and the Casbah des Oudayas

Given the choice you should fly into Rabat- as this airport is much smaller and much closer to town than the Casablanca one. If you do fly into Casablanca, take the first train out of the airport to Rabat, and unwind there. You may also want to fly out of Rabat, and give yourself an afternoon to do all your shopping in the medina (which has a very wide selection of Moroccan crafts, at reasonable prices).

Rabat is a great place to start- friendly city with a moderate amount of 'tourist destinations' but a clean medina and all the goods you may need to prepare your trip (supermarkets, pharmacies, book stores etc..). Wander into the Casbah des Oudayas through the Andalusian Gardens, have tea and pastries at the Cafe Maure. From there, walk down onto the beach and stare at Sale across the River.
Don't forget to visit the Necropolis of Chellah (a quaint mix of botanical gardens, sultan tombs and Roman ruins).
If you have the time, take a day trip to Casablanca (1 hour by train) and visit the Hassan II mosque (which has three daily tours: 9, 10 and 11 A.M.).
Wander the Streets of the Ville Nouvelle (the modern part of town) at sunset, and partake in a Moroccan national pass-time late afternoon coffee and sweets (my personal favorite is the Patisserie Majestic, on Ave Allal Bin Abdellah).

Ave Mohammed V at night

For a glimpse of Leo's Rabat, click here.