Worst transatlantic premium class: US Airways' Envoy class on the two-class 767-200. (I've previously railed on this on the US board.) Lousy food, poor entertainment options (three movie choices and a couple of looping television/sports choices - very weak for transatlantic premium service), broken reading lamp (it was *always* on). Seat recline and legroom were average. Service was average. The winelist consisted of a chard, a cab, and a chablis, all in the $15/bottle (retail) category. Except the chablis...it was probably about $10 per bottle.
Note: Other US FT'ers were quick to point out that Envoy on the A300 is a *much* better product, particularly as far as the entertainment and seats go. Apparently, A300 Envoy has been significantly enhanced beyond 767 Envoy. Also, in defense of US Airways, I've found their narrowbody F to be much more consistent than TW, NW, or HP, and on par with AA and UA.
Midwest Express sidebar: Anyone who has the opportunity to do so should try this airline. It's an entirely different experience from traveling on the major airlines, from the friendliness of the gate agents to the lack of long lines at the airport to the wide seats to the food/drink service throughout the aircraft. The FF program is very basic, but it's a trade-off I'll make anytime I'm flying a coach fare in one of their markets.