The 9 is nice and lots of them flying still. I love the Constellation, never got to fly in it, but toured one once, a thing of beauty.
The L1011 was well built, TWA used to have quite a few, and Delta just retired theirs in the last year, there is a startup airline in Thailand that is flying them. My only beef with the L1011 was the hydraulic smell before takeoff, after that, no problem.
The DC-10 is good, did a few flights on Continental and Hawaiian, never had any trouble, the MD11 had some problems, lots of them are now flying cargo.