Robert, Based on your indicated NAD model options it appears that your budget may have been reduced. No problem there as your speakers are very efficient. I would think the NAD 356BEE to be a good choice, providing a little more power than the 326BEE ( I own this model) for your quite large room and loudness preference.
I do know that many like to drive Klipsch speakers with tube electronics however in your case you seem to like the sound you were getting from your Klipsch models (which i am not familiar with) using SS receivers and the NAD integrated should represent an improvement. I am not sure that a tube integrated is the best choice for an 'audio novice' with your budget. One tube integrated that comes to mind is the Rogue Audio Cronus Magnum which can be had used for $1300-$1500. It is rated at 90wpc, is US made by a good company, and highly regarded in it's price class.
I do know that many like to drive Klipsch speakers with tube electronics however in your case you seem to like the sound you were getting from your Klipsch models (which i am not familiar with) using SS receivers and the NAD integrated should represent an improvement. I am not sure that a tube integrated is the best choice for an 'audio novice' with your budget. One tube integrated that comes to mind is the Rogue Audio Cronus Magnum which can be had used for $1300-$1500. It is rated at 90wpc, is US made by a good company, and highly regarded in it's price class.