The Business Extra supplement to Conde Nast's June issue is available only to subscribers and is not on the newsstand (I think the supplement may also be in a current issue of Bloomberg). They surveyed 3000 of their "frequent business travelers" for the following results:

BEST BUSINESS CLASS WITHIN THE U.S.

1. Midwest Express
2. Alaska
3. United
4. American
5. Continental
6. Delta
7. TWA
8. US Airways
9. Midway
10. Reno Air

BEST TRANSATLANTIC BUSINESS CLASS

1. Virgin Atlantic
2. British Airways
3. Continental
4. Swissair
5. United
6. KLM
7. American
8. TWA
9. Austrain
10. Lufthansa

BEST TRANSPACIFIC BUSINESS CLASS

1. Singapore
2. Cathay Pacific
3. Continental
4. Qantas
5. Thai
6. Air New Zealand
7. All Nippon
8. American
9. United
10. Japan Airlines

Kudos to Continental for snaring the top slot among U.S. carriers for both trans- Pacific and Atlantic routes, though it should be pointed out they don't have First Class anymore (are their business fares competitive with other carriers on the same routes?).