BKK, the Grand Hyatt is a decent hotel with a great location. So is the Shangrila.

In SYD, try the Quay West. It's a suite hotel with the best harbor view of any hotel.

In SIN, there are a bunch of hotels clumped together downtown. The Hyatt and Hilton are nice as is the Pan Pacific.

In MUC, I've only tried the City Hilton, but there must be nicer hotels somewhere. Stay away from the Rathaus! It really lives up to its name.