Speakers don't have watts. What you're seeing is a reference to the peak recommend power. You can't think of a speaker like a light bulb that's 60, 100, or whatever watts when you flip the switch. Increasing the volume control increase the amount of power being sent to the speakers. You'll be fine. There's also no problem with using a more powerful amp than what is recommended; however, you have to respect the power and not go nuts with the volume control.
I've listened to about ever planar speaker out there. One of the best I have experienced is the Model 10 by Sanders Sound Systems. A full on setup with their electronics is hard to beat for the price. They're not exactly cheap, but it fits exactly what you are looking for.
http://sanderssoundsystems.com/products/model-10-electrostatic-speaker
As for the current Quad ESL speakers, I would stay away as they have shifted manufacturing to China. The old Quads are very nice and the ESL-57 is a true classic. You will need to be cautions on the amplifier selection for the early ESL as they lacked any built in protection mechanism. Consequently, you can have issues when using very powerful amps, or at the other end of the spectrum, amps that are lacking in power. They will perform great with tube amps, and 25 to 75 watts is plenty. Just make sure it's a quality amplifier with beefy output transformers; depending on the exact model speaker, the amp will likely see some wild impedance curves.
I like Magnepan speakers because they represents great quality and value, plus they are made in the US. Unless you are buying one of their large speakers, be prepared to also purchase a couple of subwoofers. Magnepans, while having a very tuneful bass, don't have much low end grunt. You'll need to make sure you have an amp that will handle a 4 ohm load. They are also famous for sucking amps dry of all the power they can dish-out. They pair well with Audio Research tube amps and Bryston solid state amps. Do not use them with the $99 special from a big box store.
Martin Logan uses a hybrid design with a panel and woofer combo. You'll get better low end from a Martin Logan, and depending on the model might not need/want a subwoofer. But like Quad, Martin Logan has shifted a large portion of manufacturing to China. Their top models are still made in the US. Overall, I have personally never really cared for Martin Logan; but that doesn't mean you should not give them a try.
Audition as many speakers as you can and don't let me personal preferences sway you.
Finally, setup on this type of speaker is critical. They need proper room placement and room to breath in order to reach their full potential. Wall proximity must be taken into consideration as these are dipole designs and sound radiates from the rear of the speaker.