How about which cities air the most local news. I swear it seems like the Philadelphia stations air at least 25% of their air time to local "news".
Except for a break from 2-3pm, there's news all day from 4am to 11:35pm every weekday here in Los Angeles, and that's without a local cable news channel (at least one that covers the entire market).
To break it down...
KCBS: 4:30-7am, 11-11:30am, 5-6:30pm, 11-11:35pm (5 hrs., 5min)
KNBC: 4-7am, 11am-noon, 4-6:30pm, 11-11:35pm (7 hrs., 5 min)
KTLA: 4-11am, 1-2pm, 3-4pm, 6-7pm, 10-11:30pm (11 hrs., 30 min)
KABC: 4:30am-7am, 11am-noon, 3-6:30pm, 7-8pm (on KDOC), 11-11:35pm (replays on KDOC at midnight) (8 hrs., 35 mins total; 7:35 on KABC)
KCAL: Noon-1pm, 4-5pm, 8-11pm (5 hrs)
KTTV: 4-10:30am, Noon-1pm, 5-6pm, 10-11pm (9 hrs., 30 min)
If you combine the local CBS (KCAL/KCBS) newsroom, there more than ten hours of news they produce each day, and the NBC-Telemundo (KVEA) bilingual newsroom produces more than eleven hours daily.