Lol, you think you went crazy, I wouldn't worry about it. When I first discovered PAI I was so impressed by it that I went so crazy I downloaded almost all of them. I haven't downloaded any since though so there are probably some new ones to download. This is the list I have anyway:
Air Malta
Cathay Pacific
Iceland Air
Virgin Atlantic
Air Canada
Air India
Alitalia
Austrian Airlines
BA World Cargo
Continental
EasyJet
Emirates
Lufthansa
My Travel
Qantas
SAS
Swiss
United Airlines
Aer Lingus
British Airways
Iberia
TAP Air Portugal
Aerolineas Argentinas
Air France
Air New Zealand
American Airlines
BMI
Cargolux
CSA
El Al
KLM
Olympic
Ryanair
SN Brussels
Turkish Airlines
My favourite is probably Iceland Air, there are some 757s and the paintscheme looks really nice.
I haven't noticed too much of a problem with performance because there are so few parking spaces at most airports that there still aren't many AI aircraft anyway. Things do slow down at EHAM and EGLL though because I have edited them in AFCAD so there can be loads of AI, it does tend to mean continuous Go arounds from the ATC when I try to land though.
I don't know why I bothered with all of those different airlines though because half of them I have never seen on FS. You are right, it is best just to stick with the European ones really, I mean what are the chances of me flying to Argentina or New Zealand, I'm not sure Euroharmony even has flights to those places.
