Like i said earlier. I had the same problem with my car, almost 2 weeks ago. Engine crank was very very strong. since we replaced our starter not long ago. The battery wasnt the problem, bcuz we replaced it this yr as well. Our problem was the distributor cap, it was cracked. Sometimes it would start, sometimes it wouldnt, the reason why it would start n not start sometimes was because sometimes when i start, i was just starting when the distributor was distributing enough to get it started. so i was lucky to get it started at those times.

But, i also agree, not the battery. check the minor things b4 u spend money. Ur problem sounds very very very very familiar with my problem. No engine lights turn on, everything was ok, as if the engine was in perfect condition. Check the distibutor, take out the plugs, n take out the distributor, n look for cracks. But i do hope u dont spend any money u dont have to be spending on ur car, especially during Christmas season.