Next spring I plan to do a DONE5 starting from LHR to SYD and I understand there are fee, etc. differences between the airlines that issues the tickets. I can either fly BA or QF for the first flight.

Is there a cost advantage to buy the ticket on either QF or BA?
Can I buy the ticket on AA although the first flight is not on AA?

Thanks in advance.

There is a huge cost advantage to buy the ticket through AA because the fuel fines are much lower or not there at all. This can be a $1000 difference compared to BA or QF. Who has the first segment is irrelevant. In theory, any OW airline can ticket even when they don't have a single segment.
In reality AA likes to see some AA segments in there. If you are really unlucky, AA might insist on an AA overwater segment (can be a codeshare). But normally there shouldn't be any problem when ticketing through AA.

Their RTW desk is very knowledgeable and good to deal with.

By the way, you can fly a lot more airlines for the first flight. CX comes to mind but also RJ, JL or AY.

Just a couple of cautions. First, remember you cannot re-enter the country of origin and leave again. This becomes an issue with UK-issued tickets because of the importance of LHR within the Oneworld scheme of things in terms of routing. It may not matter to you depending on your itinerary, but intra-Europe travel can become a nuisance later if you can't transit the UK between, say, N. America and, say, northern/eastern Europe.

Second, you probably know that RTW tickets are priced differently from one country of origin to another. With today's exchange rates, a DONE5 purchased and originated in Poland is almost �1000 cheaper than one purchased in Britain; it's around �750 cheaper if purchased/originated in Sweden. Aside from the obvious price advantage, starting/ending in some other European country means you could transit in London later if you need to pass through. I'd also mention that ticketing through AA might save a lot on fuel charges, and both WAW and ARN are served by an excellent General Sales Agent (GSA) for American, Tal Aviation. The combination of ticket price savings plus fuel surcharge savings could well be very significant in total cost terms. Certainly it's greater than the price of a short flight to Warsaw or Stockholm.

The down side of starting elsewhere in Europe is that it automatically obligates two of your four available European segments - one to get from Poland/Sweden/wherever to an intercontinental gateway from which you can travel on to Oz/Asia/Americas/Africa etc. and the other to get back at the end. This may be a big enough drawback that it's worth the �1000++ in extra cost, but that's up to you.

Thanks for the suggestions. I decided on LHR because it is easy to get to from MIA and the RTW is cheaper than from the USA.

We have made several RTW's over the years. This one has the objective of visiting or revisiting some places we enjoyed and go a long way toward again qualifying for EXP.

Tentatively the trip starts in mid March and is
lhr-syd-drw-per-nrt-bkk-nrt-sin-hkg-jfk-scl-ipc-scl-mad(x)-amm-dxb-lhr (61320 miles).

I will break the trip up when I get back to JFK and resume about a month later. The places that are visited for milage or routing are: nrt (twice), scl (repeat) and mad.

I really want to visit:
Europe -- AMM and DXB
SP -- SYD, DRW and Perth
Asia -- SIN, HKG, and BKK
South America -- SCL and IPC

If anyone sees a better routing that does not significantly reduce milage, please let me know.

Another downside of starting in the UK is APD.

Next UK Spring that will set you back an additional �110 (�170 from Nov '10).

Indeed. Start in South Africa and add one continent. Much cheaper. Next you use that money to buy airpasses for Australia so you do not need to burn your segments there.

You will add considerable mileage as well. You might need a reroute and do AMM and DXB first. You could drop JFK since it only adds a continent.

How about:

CPT-LHR-AMM-DXB-LHR-EZE-SCL-IPC-SCL-SYD-DRW-PER-DPS-NRT-HKG-JNB

Mileage Monkey says it is invalid but I believe there is a flight between perth and denpasar on QF. If it now is on Jetstar you may need to move it around a bit.

I knew that UK had an APD, but did not know it was planned to increase so much. So, I will reverse my flight order and save a little. Also I can change JFK to LAX, which will add an AA flight between SCL and LAX. This should make AA happier to ticket. My new routing would be:

LHR-DXB-AMM-MAD-SCL-IPC-SCL-LAX-HKG-SIN-NRT-BKK-NRT-PER-DRW-SYD-LHR (60973 miles)

I choose orignating from LHR over Africa because of cheap fare and ease of getting there from MIA. Also the USA stop allows me to break the trip up.

Thanks again. Any more suggestions?

You won't avoid the APD by starting LHR-DXB. Any premium cabin/longhaul destination from LHR (of which both AMM and DXB qualify) will attract the APD at the highest level. So if your route reversal was intended to avoid it, no dice.

Remember too that the rules allow a transit-without-stopover in N. America going to/from S. America, so you might think about ...DXB-AMM-xJFK-SCL instead of AMM-xMAD-SCL. RJ premium service is supposedly quite good, plus I believe it nets more miles. Remember only two stopovers in the continent of origin, so assuming for you those are DXB and AMM, then MAD would only be a transfer anyway.

The LAX-SCL flight is on Lan metal; the AA code ought to be sufficient to cover any questions raised by the AA RTW desk as far as AA segments is concerned; you could also use the AA code on LAX-HKG.

For what it's worth, WAW-xLHR-SYD-DRW-PER-BKK-SIN-HKG-JFK-SCL-IPC-SCL-xJFK-AMM-DXB-xLHR-WAW would save you something like US$2000+ over the London origin owing to cheaper base fare and avoiding LHR origin or stopover (thus APD). Fewer miles maybe because of the absence of the NRT segments in Asia, but for $2K you can make up those miles/EQP pretty easily outside the RTW.

The APD is slightly milage dependant, for premium fares 2K to 4K miles it is 90 BP and for over 6 K it is 110 BP. Granted only a slight savings, but I don't care which way I go. Should I care?

Great suggestion! Better service and a few more miles.

Another good suggestion.

I am going to pass on starting in WAW, cheapest air is $500+ more and not as "neat". Thanks anyway.