You're better off with a more powerful amp than what the speakers are rated for
Agree 100% - this is known as 'headroom'.
If you have a requirment of, say, 50wrms per channel you can either get an amp that delivers 50wrms (and run it at full chat) or source an amp that will run at 100wrms (for example) and run it at 50% of its ability.
The greater the headroom (i.e. difference between power requirement and power capability) the cleaner signal your speakers will get, as the amplifier is working well within its 'comfort zone' (i.e., zero chance of it sending a clipped signal to the speakers, as per Ben's comment).
It also means that, come speaker upgrade time, you can theoretically get a greedier set of components (in terms of power handling) without necessarily needing to upgrade your amplifier, which you'd need to do if you match them watt for watt.
People speak about pairing power handling of speakers and amplifiers, but most fail to understand that you can run an amplifier at less than full chat. You do need to balance the output of the amplier with the speakers, yes, but the output can be adjusted down, and therefore does not automatically mean its total ability must equal that of the speakers.
Power output of an amplifier is variable; buy high, and de-tune (adjust gain).
This gives a nice clean signal with a future upgrade path...
