It depend on the temperature of the room the cage is going to be in. If the room drops below 75 degrees F then a heat lamp will be required as heat tape doesn't effect the temperature of the air in the cage, it only heats surfaces it comes into direct contact with.

I believe the ideal setup is a combination of both. Use heat tape to generate the hot spot temperature of 88-92 F then use a low wattage infrared heat lamp like this one: http://www.petsmart.com/product/inde...AvailInUS%2FNo (50 or 75 watt) centered on top f the cage to maintain the air temperature in the entire cage between 78-82 F.