Please advise on planning the trip of a lifetime

The first thing people will likely tell you, and that I will too, is that you can't rely on getting work wherever you are - you'll be competing with residents for jobs, so unless you have a specialized skill that they don't, you could wind up not being able to get anything. With that in mind, budget appropriately. I can't answer your question about the cost of South America, but it will really depend on what countries you'll be in. Places like Peru, Bolivia, and Ecuador are reportedly less expensive to travel than Brasil and Argentina, for instance.

I spent very little traveling in SEA, and I know people who did it for less than I did - an average of US$25/£17 per day, but that number changed depending on the country. Malaysia, for instance, was on the higher end, while Cambodia, Thailand and Indonesia were very cheap. If you do a search through the forums you can get a daily budget estimate, and then draw up a chart to estimate how much you'll have by what date. If your travel dates are somewhat flexible, just go home when you run out of money.

I don't think you'll have enough money..of course,it depends on many things (where you stay,what you eat,which countries,which activities etc etc) but your budget looks very low to me.

That 1 month in Oz and 1 in NZ will eat up most of what is left of your money......

Personally i'd consider skipping that part (or if you have the RTW ticket anyway,just have a very short stopover..say a week in Sydney for example)...and keeping what is left of your cash for South America.

As above...Brazil or Argentina will cost you three-four times as much (per day) as Bolivia and Peru.

Thanks guys, this has given me a lot to think about. I really appreciate your advice :)

To be honest, my reasons for going to Oz are convenience and the fact I know I would enjoy it. Plus my RTW passes right through, so it feels silly not to! Also, as a virgin traveller, I think I would appreciate the respite of being settled in one place too. I can definitely see the benefits of staying in Oz for like 3-4 months and working most that time. As far as wasting my working holiday Visa, I doubt I would ever seriously consider living and working in Oz any longer than that, so 4 month would not be a waste in my opinion. If I consider at least one month's travel in Oz and NZ as a definite, I guess my question boils down to this - should I work in Oz for a bit and then travel there for a month, then on to NZ for a month and finally spend a month in the US OR should I pass through OZ and NZ and hope my remaining budget will allow me to have a good crack at South America? My fear is that if I choose the latte, I will be so horrendously poor that I don't get to fully enjoy my time in South America!

If you can find a job, take it for sure, sounds like a good plan, and then travel around a bit afterwards. You can always go home if you run out of money. How does it look when you estimate your daily budget? How much do you estimate you'll have by the end of SEA? Have you searched the forums for daily budgets to work it out?

Well by the end of SEA I will have at least £5,500 remaining after 5 and a half months of travel. I would love to travel straight through Oz (like spend two weeks there) but I'd want to do at least 1 month in New Zealand for sure. I have been told to budget at least £2000 per month, so a month and a half of travel would leave me with just £2500 for South America. I've heard places like Brazil are very expensive and if I went to South America I'd want to spend at least 3 month there, so I guess that remaining cash wouldn't cover it. I could always just alter my RTW ticket to finish in the US and do a six week road trip instead, but I'd feel like I was missing out on South America! I'm not really sure what to do.

You could always opt to skip Oz, travel for a month in NZ, and then finish in South America, in the less expensive countries, as mentioned above. Even if you're only there for a month or two it'll still be worth it. Just pick one or two countries to focus on, and if your money last longer, it'll be an added benefit.

Ditch the US; it's expensive, and South America is probably way more interesting, and bound to change at a faster rate. If you finish in the US your money will drain much, much faster than in South America... I live here, I would know. The US will be here for your next trip.