Am just looking for having custom websites for few countries

At present am using .com at present to serve everyone

So for now in the future am going to serve
Australia
UK
Canada
NZ

Am in immediate next month am going to start with Australia

So i need your suggestions on how to make up country based websites..

Should i go for

country based subdomains
au.myweb.com

or country based subfolders
myweb.com/au

what are possible solutions with me

The main thing is that i want few pages to be common for all people and rest different for everyone depending upon location

this is confusing me up and i need some guidance for this

Any links to setting up such type of website would be great

thanks for your time
Regards
jamie

ps: sorry for typo in title