Accumulating miles for my 1st ever first class flight - any recommended airlines for best experience?

To me, your miles are stored where? With Krisflyer or banks? If Krisflyer, just aim for the SQ Suites. Don't think too much. The other one you can consider is Lufthansa first class on board their 747. Plus if you fly out of Frankfurt you get to try their first class lounge, which has a whole building to itself.

If with banks, espcially Citi PM, aim for Air France La Premiere. I have yet to come across any negative comments or reviews on La Premiere. And the lounge at CDG is awesome.

Another worthy mention is Cathay Pacific First Class, and the lounges at Hong Kong airport.

All in all, always aim for Middle Eastern or Asia carriers first class. The services onboard trumps American's carriers.

Singapore Airlines FTW. Ex-Sin for the The Private Room experience!