I am planning Sydney - India - Madrid (travel by land to Greece) - New York (don't car where in Europe i fly out of) - Miami - Vegas - San Diego - Sydney.
Any thoughts on where to get the cheapest RTW tickets. open to suggestions such as ryan air/easyjet around europe and equivelent in the US.
Little known to many (goodness knows why), but it's possible and a lot cheaper to get split tickets en-route. Any travel agent will show you how it's done.
Check out Air Asia's prices (and the routes they do). They'll get you from Australia to Europe.
Once you're in Europe, look at Jet2. They do limited O/W budget flights from Europe to NY (Newark). Their service is amongst the worst on any airline in the world but they're cheap, very cheap. Not cheerful though.
The USA has numerous budget airlines that fly across and up & down the country. Just beware that USA prices don't include tax. Their prices all look rosy at a few $'s O/W till the tax is added on.
It might sound a bit messy to sort out flights with one airline, then another one to fly you with someone else that isn't affiliated. However, get your RTW ticket price, then split it. You may be pleasantly surprised to the tune of several 100 AUS$ or more.
STA travel. Should have an office in Oz in a few cities i think. Was cheapest for me.
I think what may be a stumbling block on splittlng up the air tickets, the is the high price of a one-way ticket from Europe via USA back to Australia. You might do better by getting one of the multi-airline deals available through STA, Flight Centre or on http://www.bestflights.com.au/cheap-flights/phone-flights-results/Round-World-Flights.
One point: taxes are excessive flying from London!