Never give up!
Well atleast I wouldn't if I spent a huge amount of time creating something.
Other possible reasons:
1. If you have edited units/buildings, you may have done something wrong and thus placing it on the map may be causing the crash.
2. It might not be the map, but a graphics related issue. Try lowering your settings and see if you get lucky (IIRC, there were some users having crashes on very large maps a while back).
3. Recreate the map via the resize tool in WorldBuilder (IIRC it creates a new map by default even if you dont change the size) without the cities/units and see if that solves anything.
4. If playing with a custom civ, make sure all necessary supporting XML entries are present (leaders, religion, unique unit/building choices).