Shifting currency values make the United States a better bargain for foreigners living in U.S. cities this year, a private research group said.

The 2008 Mercer Cost of Living survey, comparing 143 cities on six continents, found that Moscow is the most expensive city in the world, with prices there propped up by the strengthening ruble, CNNMoney reported.

Tokyo is the second most expensive city in the world, trading places with London, which ranks third on the list.

A cup of coffee serves as a dramatic case in point. A cup of coffee that costs $3.75 in New York City goes for $6.75 in Paris, $6.32 in Dublin and $5.15 in Berlin, CNNMoney reported.

The declining dollar shifted the ranking of 19 U.S. cities, Mitch Barnes, a principal at Mercer said. In the past year, New York dropped seven spots to No. 22. Los Angeles moved from No. 42 to No. 55 and Washington slid from No. 85 to No. 107, the report said.

Cities with stronger currencies are more expensive for U.S. expatriates. Perth, Australia, is more expensive than Los Angeles, jumping 31 spots to No. 53.