Ok, so when I made my Bnet account, I had to say I was from Australia because when I tried to progress as UK, it wouldn't let me. Yey for Blizzard...
So, I sent a ticket off last night and they said I need to send them ID to get it changed. Well, screw that^^
I want to play D3 on the European servers, but I'm 'from Australia' according to my Bnet account. Will it actually make a difference? I'm not very technical, so excuse me if this is an obvious question
What determines your region is where you live. If you live in UK then your region should be UK.
I don't know if this makes a difference. Even if your region is set to UK you can still change the server in game. The only thing that matters is if you want a different currency on the RMAH (which you can't switch and which is determined by the country you live in).
Yeah you'll be able to select the UK servers when you play, but you'll be tied to the NA Auction House UNLESS you bought a physical UK copy of the game, in which case you'd be with the EU auction house.
Just on a additional note, yes, you will be able to play on any server you want, and yes, you will be able to use RMAH only on server where the game was registered, but you will be able to use GAH on any server. So, while you won't be able to trade real money on European server, you will be able to trade gold on it, and then you can trade gold for real money in your native auction house.
Actually, other than being able to play on US with a EU copy and on EU with a US copy, none of what you guys are saying have been confirmed. Some is assumed because it makes sense based on certain comments made by Blizzard in the past, but Blizzard were never very clear about this nor did they actually confirm anything officially. If you go ask their support about this, they'll simply tell you it hasn't been officially announced yet.
If you don't intend to use the RMAH then you should be fine. If you change your mind in the future, though, you might have problems (maybe unless you actually do have an ID to show them, and of course assuming you registered with your real name etc).
you'll be tied to the NA Auction House UNLESS you bought a physical UK copy of the game, in which case you'd be with the EU auction house.
Speculation, unless you have a link that confirms that. It's much more likely that retail purchase location makes no difference at all. Why create complexity in their systems by having exceptions based on purchase location when they can just do it by B.Net account settings?
For the op; the only problem you might have (and this is me speculating because I haven't seen any confirmed information either way) is that if your account is set to AU you might not be able to play until AU accounts unlock (which will be when the NA servers go live). If I'm correct about launch locks being based on account only then this seems likely. If it has something to do with retail purchase location then it's not likely to be a problem. There could also just be IP checks to check you are in the right region. In which case there would be no problem.
Blizzard really needs to hurry up and clarify how things are going to work.
Serial numbers of retail copies don't mean anything at all. Only thing that matters is in which country is your battle net account registered. So if you registered your battle.net in Australia and put in UK serial you can only use Australian Rmah. Also you cannot transfer items, gold or characters from one server to another. If you still want to play with your UK friends, of course you can regardless of where your account is located, but you will not be allowed to your real money trading, and everything get on European servers will stay on European servers. If you want to get any kind of real money for that, you will have to use third party websites. Btw, you haven't said where are yo actually from, so I am assuming blizzard is correct to assign you to Australia (IP based)? In that case amazon.co.uk would refuse to ship D3 or any other game/movie/music outside of EU, and you would need to have a third party receive it and forward it to you, which wouldn't really save you that much money (even if the basic price is only 50USD), not to mention it would take weeks to get to you.