You'll also want to use Paypal for a payment option - banks are fucking tight on giving out merchant facilities for online shops.
+1
That said we had some trouble with PayPal for a site once - for some reason that PayPal could never tell us most transactions were being blocked for security reasons.
If you have a semi-rational hatred of PayPal then you can use eWay or something ... but you'll probably need developer help for that as common eCommerce packages probably won't integrate with the more esoteric payment gateways out of the box.