<font color='#000000'>The power rating on any good speaker is almost meaningless, efficiency is more important, how loud is it with a given power level. You can't really have too much power. Distortion is what harms a speaker, distortion causes heat, heat damages the coil. When an amp is driven into clipping it starts to produce distortion. Usually, lower power amps with very little current are the culprit of this. Any decent amp with with 30-watts or higher is going to be fine. You wouldn't want a million watts of course but any well designed amp 30 to 500 watts that is not pushed into clipping will never cause an issue. How your amp is designed is more important then the power rating of your speaker. You are perfectly OK to have a speaker rated at 100-watts and driving it with a 200-watt amp.
I would stay away from speakers that have less than 85db sensitivity at 1 watt 1 meter, unless you have a very powerful and clean amp. Those types of speakers are going to be harder to drive and will cause lesser amps to clip faster. Most decent speakers are well above that.</font>