From the city pack, my top5 would be:
1. Traffic Jam (most recommended, great design, gameplay, extra art)
2. Doomcity (another very well done level, like all pipeline maps)
3. WGCity (I'm not a big fan of "modern" style levels, but this is a mighty exception)
4. City of Screams (not a very well designed map, but I love the atmosphere)
5. AMC Pleaser (I think I must include this one
)
More great city maps that not included:
Fernocity (mainly because I was helping the author with some feedbacks, and because it's a good map... his other map, Area 69 is also overlooked)
Operation Get Bike Back (another stuff like WGCity)
NukeCity2 (is this available anywhere?? the one with the dukebots... I loved every piece of it... much better than NukeCity1)
The Dream series level 1 (I don't care about the sequels, this is the thing! The best part is obviously the one not in the city
)
And more great city maps within' episodes:
Last Reaction and Water Bases levels: Alien Detraining (excellent mix of slumtastic urban style and an authentic spaceship), Back to LA (OMG, this thing is jaw droppingly brilliant stuff)... and also the boss levels after them
JJ Duke: more like sentimental favourite, but I like the levels in episode 3, and the boss level in episode 2 too... some levels had a great Hollywood Holocaust atmosphere to them
aaand last but not least:
Duke Forever 2013 level 1: It's a domination made by Gambini.