Best banck in Sydney

In order of size;

Commonwealth.
National Australia.
Westpac.
ANZ.
St George.

"Best" doesn't mean a great deal when it comes to banks....

I'm not sure what a regional bank is. There is a small comunity based bank called The Bendigo Bank. There are industry and community based credit unions, is that what you mean? If so there aren't really any that stand out. The ones that used to have turned into banks now, St George for example.

Best service - St. George, but hey I head technology architecture there - so maybe I am biased! St. George has won bank of the year - best customer service of the year for about 3-4 years running now!

There are 88 banks in Australia, by size

Big 4: NAB, Westpac, CBA, ANZ
Super Regionals: St. George, Suncorp Metway

Then lots of small banks and many excellent Investment banks (Macquarie, Deutsche, JP Morgan etc...)