IME, you'd be quite well-served with an AC membership augmented with a CO President's Club membership...the PC membership gets you into all the SkyTeam lounges and pretty much covers most places an AC is not available.

Alternatively, you could supplement your AC membership with Priority Pass--I have no experience with PP, but as has already been mentioned actually being an AC member is invaluable during IROPS...and I've seen the same signs TrojanHorse mentioned, so that's a consideration also.

An astute analysis of your typical/anticipated destinations should reveal the best course of action to you...

cheers and good luck!