Airlines with top ratings: Singapore Airlibes, Malaysia Airlines, Eithad, Emirates, Air New Zealand, Kingfisher, Thai Airways, Cathay Pacific
Airlines that are decent but dont expect much from but will get you there: Air Asia X, Quantas, Royal Brunei, Gulf Air, Lufthansa, KLM, Air France, United, ANA, JAL, Tiger Airways, Jetstar, Royal Nepal Airlines, Korean Airlines and ever other airline from China.
Airlines to avoid like the plague: Air India, PAL, British Airways and every other American airline.
Can't comment about South African or South American airlines as I haven't flown on them before.