As I've said many times before, I love maps in my planners. I actually use them, and often. I especially use time zone maps, since I live overseas, and have friends and family all over the world.
The best maps I have ever seen in bound planners are in The Time Traveler planners (click here for their website). (Edited to add: the position of Best Maps now goes to the Collins Classic Manager planner. Its maps are complete with topo and road information! Click here to see my review and photos of the Collins Classic Manager planner.)
I bought my first Time Traveler planner in 2005, mainly because of the maps, and bought another one in 2009. They have an excellent time zones world map (which is also one of the very few I've ever seen which accurately notes that Nepal is in its own time zone of 45 minutes, not on 30 minutes like India). Click on any of the photos below for a larger view.
Filofax has some excellent maps. I like their pull-out map with the time zones on one side:
Quo Vadis planners have excellent maps of all the continents that are nicely detailed and very comprehensive. Recently I specifically looked in my Quo Vadis Minister planner to see just exactly where Jakarta is and what's near it:
Letts noteletts notebooks have very nice time zone maps: