Traveling through S.E.A + South Pacific

[tuge]

My friend and I are planning a 6 month trip around South East Asia and Australia/New Zealand. We will be traveling with a very tight budget. We've been looking into RTW prices, and they all seem to be pretty pricey. There's another option that we're considering, which is to purchase a one way ticket to our first destination, then purchase another one way ticket back home and just buy tickets to different parts of the countries while we're there. Here is a rough idea of the places we're planning on going to. Just wondering what people think and if you can point me to some good sites with affordable flights.

Option 1:
Purchase a one way ticket to London and from there, purchase a ticket into Bangkok.

Option 2: Purchase a one way ticket into Bangkok and during our return home, purchase a one way ticket from Sydney back to Vancouver.

Places to we're planning on going to:
Thailand
Cambodia
Laos
Vietnam
Philippines
Hong Kong
Singapore
Malaysia
Nepal
Australia
New Zealand
Fiji

Also, if anyone has done a 6 month trip through these countries, what was your budget like? How much money would you recommend we bring?