Great reviews, Dreaded Gazebo!
Ticket to Ride is another big title that hasn't been mentioned. I think of Settlers of Catan, Carcassonne, and Ticket to Ride as the Triumvirate of intro games. These three are the big gateway drugs.
Hollywood Blockbuster is my favorite auction game. Basically you're trying to complete films and you have to outbid your opponents for talented actors, directors, etc.
If you like Carcassonne, then you may also enjoy
Metro or
Taluva, both of which employ a tile-laying mechanic.
I'll also put in a plug for
Last Night On Earth, which is hands-down the best Zombie game out there. Also, if you can find a copy of
Betrayal at House on the Hill, buy it. It's out of print. Actually, almost all of the non-Axis & Allies titles released under the Avalon Hill label are being discontinued (including Nexus Ops, which I see is on your list), so if you come across any you think you may want you should probably go ahead and buy them.
Finally, I'll put in a plug for
1960: The Making of the President. I just got this game a couple of weeks ago and it's my current favorite. It's a two player game: you play either the Nixon or Kennedy campaign in the 1960 election and battle for control of states on a 1960 electoral college map of the US. It's a great one to have on hand for this election year!