Speakers for a very large room?


Reader of posts for a few years but have not posted a serious question until now. Currently have McIntosh integrated tube amp with some old KEF speakers. While I enjoy it in my current setting, I am moving to a house where my listening room will be 30' x 40' x 10'. It has polished concrete floors. Sounds like a grocery store but it is not. I suspect I will need to change speakers but really have no clue where to start. I listen mostly to progressive rock but also anything in the same general area. I don't know where to start with such a room? I am at least 3 hours from any major city. I did experience Treo CTs once and to bright for my ears and Wilsons but did not care for the visual appearance though liked the sound better. It was a few years ago so can't better define what I liked.  Not a great resume of listening experience but it is what it is at this point. For some reason, which may be completely wrong, I am thinking electrostatic may work well in this setting. I could easily move them 5 feet out from the back wall but then again I really don't know what I am talking about. Any kind comments would be appreciated.

Rich
ricmci
Excellent suggestion on the room treatment  An empty room with hard sides will slap echo like a bastard without treatment. Carpets on the floor, drapes on any windows etc. tame things considerably.

While one could probably be pretty happy with some small monitors in the middle of the room, I understand the urge to experience speakers that  wouldn't have sounded very good in your previous smaller room.

Personally, I'd be looking to the second hand planar speakers and the suggestions of Martin Logan, Magnepan, SoundLab Apogee, are all good, and you can get used for decent dollars.

You can also look to conventional speakers that would have been a bit compromised by small rooms.  

You may well be looking at an amplifier upgrade at some point, depending on what sort of load the speaker you choose presents.
Hey, I too have a large room above my Garage 48x18x7.5' that I'm finishing.  Both ends of the room are pre-dedicted to other functions, an audio workshop at one end, and live music area at the other, and in the middle on the long 48' wall I plan to have a listening area.  Any obvious issues with this setup?  The side walls would be literally be 24' away in either direction.  Also running the full length of that wall is a knee-wall angle starting at 6' to 7.5' about a 2' angled wall, which would be the back wall behind speakers.  
@ricmci for room correction I strongly recommend Dirac Live products. Their software corrects phase (timing) and frequency response of your speakers and the room. It can make a significant difference.

While many acoustic treatments don't exactly look like works of art, you can find (or create) acoustic treatments that look good and fit into your decor.
Ok. I have to admit that I am one of those loyal McIntosh customers but would be willing to eventually upgrade in-brand.  They have treated me well over the years and I love the warmth with the kind of music I like. Might be short sighted but it is what it is.  Anyways, I am hearing room treatments and klipshorns with subs over and over. Much appreciated. I will start there. The one thing I love about this hobby/addiction is the ability to not do things hastily. Sit back and reassess. If you think you missed a good deal, it will eventually come around again.  Thanks to everyone for your insight!