This question has come up before, and I'd advise you to do two things:-
a) Have a look at this website, it is very useful
http://www.fitfortravel.scot.nhs.uk/
b) Get an appointment with a GP, who specialises in Tropical Diseases. Your local GP practice should know.
Different parts of the world have immunity to different drugs. If you are going throught SE Asia, you could potentially have to take 3 different types, all with different doses, different side effects etc.
When I went we only took them in Laos, Cambodia and India (and possibly Vietnam). Naver taken Larium but it has a reputation for depression. One of the malaria pills makes the pill ineffective.
Get some proper advice, if you get it wrong based on advice from here, nobody will be around to help you should you get recurrent malaria!!!