Scavenger: Great post - nice to have a summary of the current policies.
Note to anybody flying Lufthansa: please read the policy he posted closely - LH is one of the few airlines that does not consider ski equipment to be substitutable for one item of your checked baggage. Many airlines let you consider a ski-bag+boot-bag as "1 item" in place of 1 of your bag allowances. Lufthansa does not - they will charge for the ski bag even if you don't have any other checked bags.
Few other notes:
Andrew R referred to "the 'land of the fat' refuses to align with the baggage limitiations of the rest of the world and one can generally get away with two pieces to 32kg." What this boils down to is that throughout the airline industry worldwide, there is either the "weight concept" or the "piece concept". All international itineraries arriving in or departing from North America (not just the USA) normally get the "piece concept". Typically this is 2 pieces, and typically is 22kg/40lb maximum weight for each piece. 32kg/70lb(roughly) is fast disappearing as a free limit for the "piece concept".
Keep in mind that all legs of a North American itinerary, including connecting all-domestic legs within Europe or South America or elsewhere, are supposed to get the "piece concept". If you're flying from Dusseldorf to Frankfurt and then from Frankfurt to Denver on Lufthansa, you're supposed to get the more generous "piece concept" even on the DUS-FRA domestic German flight. You may have to point that out firmly to the check-in agent, since they might automatically think "weight concept" for that domestic flight.
However if you are a top-level elite with an airline alliance, you may have a a higher allowance; either extra weight on "weight concept" flights or extra piece (and perhaps extra weight per piece) on "piece concept" flights. For example, as a Star Alliance Gold Elite (due in my case to being Premier Exec with United, but it could also be from SEN with LH, SuperElite with Air Canada, Platinum or Chairman with US Airways, etc.), I supposedly get a piece-concept baggage allowance of 3 pieces instead of 2, with weight of 32kg instead of 22 kg limit per piece. Supposedly on any of the 17 Star Alliance airlines. Don't count on the higher limit unless you have high elite status in that airline alliance.
I'll let you know whether or not that was honored in August, after I fly to Portillo (Santiago) on an all-Star Alliance mixed-airline itinerary of United, Air Canada, and Swiss (United to Buenos Aires, AC to Santiago, Swiss from Santiago to Sao Paolo, and United from Sao Paolo back home). I should be able to check my skis as "one bag" given United's policy, and I should be able to take up to 3 bags at up to 70 lb each per Star Alliance Gold policy. But we'll see. My return journey begins on Swiss, and they're owned by Lufthansa, so I think I'm going to get hit with a charge for the skis on the way back. On the way down I should be fine, since my journey begins on United and continues on Air Canada, both of which have the "skis/boots = 1 bag" substitution policy.
Andrew R, T-Square and others with Sport Tubes - have any of you had problems with US TSA or other countries' security not properly re-securing the SportTube after inspection? I've been hesitant to get one of these, since I've heard stories that after they open then, they don't re-secure the closure, and thus the tube pieces come apart and skis get dumped out during transit. These were initially designed pre-9/11 and thus designed to be locked, with the lock holding the pieces together. Now that you can't lock bags with secure locks, you apparently have to use some kind of removable closure or a "TSA lock" - and I've heard that TSA doesn't put the pieces back together. This might be outdated rumor so I'd appreciate your more current experience - I might get one before the Portillo trip.