If you can guarantee the opportunity to fly LH's A340-600 YVR-FRA, I'd go for it.
Otherwise, Air Canada shouldn't be half bad. No matter what, you'll have a personal video system (AVOD on A330s & select-A340s, PTVs on 767-300s & other A340s, and DVD players on ex-Canadian 767-300s). Also, all Air Canada flights to Frankfurt are featuring the new ExecutiveFirst service (improved menus, blankets/pillows, amenity kit), which is supposed to be quite good!
Derek