You must take advice from a real DOCTOR, preferably one specialising in Tropical Diseases because what you need to take depends on where you are going to be and how long you need to take it.
However, just for information, DS works for an NGO in sub-saharan malarial areas.
Mefloquine (Lariam) is only good for 1 month's cover and has nasty psychological side-effect.
Malarone is good for 2 months' cover.
Doxycycline is an antibiotic, (usually also the medication of choice to cure cholera!!) which also acts as an antimalarial. It can be taken for up to 6 months. Note that long term use can affect the liver in later years. It is also important to keep out of the sun when on Doxy because it makes your skin react to sunlight.