Preparation

Mandatory: Passport, credit cards and money, tickets
Optional: Everything else

Due the relative short time between deciding to go and actually doing it, I done very little planning for a trip that long. how can you plan in a couple of weeks what I'll be doing for a year ?
I have started by making a list of countries I would like to see and read about it on Wikitravel. I became aware of the danger I will expose to (and I am no taking here about plane crashes, being victim of bomb plot or kidnapped, but the ones more likely to happen, like food poisoning and diarrhea, malaria and dengue fever, traffic accidents, having my passport/credit cards/money stolen, getting lost).
I have taken shots for hepatitis A & B, diphtheria, typhoid, tetanus.
I ignored Japanese encephalitis. For dengue fever there is no medicine. I will probably not take any medicine for malaria (strong side effects) but I will use heavily mosquito repellent in the danger areas.
I made an excel spreadsheet with the countries, months, the weather in those months and visa duration. Based on that I decided upon a route, Since then I have change it two times, and it is just a rough guide.
I have bought one way tickets for the beginning of the trip. The rest of the trip I will figure it out as I go along.
As for the things I will be taking, I thing this is the least important aspect of the trip. The idea is to be as light as possible. The list looks like that:
-passports
-money
-credit cards
-tickets
-big backpack
-small backpack
-driver licence
-diving card
-wrist watch
-sun glasses
-flashlight
-trekking GPS unit
-cellphone, charger
-memory card, USB stick, USB cable
-sun screen
-toothbrash, toothpaste, shaving cream, razors, soap, nail cutter, dental floss, towels
-socks, boxers, short pants, swimming pants, t-shirts, one pair long pants, long-sleeve t-shirt, sweater, rain coat and rain pants, flip-flops, running shoes

Expenses
Vaccination 166+160+220 RON
Train ticket Bucharest-Istanbul 215 RON
Airplane ticket Istanbul-Bangkok 366.25 euro
Airplane ticket Phuket-Singapore 1605 bath