What is the best way to get from Bangkok to Phuket?

The best way to Phuket is to Fly. You can either use one of the full service carriers like Thai Airlines or Bangkok Airways. Also available are discount airlines like Nok Air and Air Asia. Thai Airlines is about 2,500 one way while air asia is about 2,000 one way. Kept in mind these discoount airlines have small weight limits or baggage and excess can raise the price. You can google the web sites of all of these airlines and see which one is best for you. Train does go directly to Phuket you would have to take the train and then a bus. To me it is not a good idea. Other way is bus. You can take a 12 hour bus ride in either a 24 or 32 panger bus from the southern bus station depending on which cl of bus, the must expensive is the 24 VIP bus at about 1,000 baht. The buses leave in the evening and arrive in Phuket the next morning.