I have another vote for Australian beef. If you are in Sydney, try Kingsley's Steak House, or if you are cooking your own food (summer BBQ maybe?), go to Glenmore Meats and buy a "Young Scotch Fillet". Glenmore meat is a wholesaler with a small retail store attached. They will cut the meat to your request.
Whole Foods sometimes sells Australian or New Zealand grass fed beef and it is great.
In the US, Strip House in NYC has the best steaks I have had, but if you are on a budget, Outback Steak House have (at least last time I was there) a selection of Premium steaks, which I think are of a similar standard to Morton's. Outback & Morton's share the same beef supplier, so I was not surprised.
www.kingsleyssteak.com.au
www.glenmoremeat.com.au