Many great suggestions above. In your price range you really can't go wrong. However, the "cat clause" may be your biggest issue. One suggestion I did not see above is Epos K2.
I had a pair and loved them. Got a great deal from Music Direct on them. Silk dome tweeters (perhaps give a more laid back sound) may be a good match for your NAD. They are 89 dB sensitive, front ported, and best of all comes with a cat friendly fascia.
Here is a review I found.
http://www.epos-loudspeakers.com/wp-content/uploads/2015/01/K2-Hi-Fi-Choice-Web-Quality.pdf
I had a pair and loved them. Got a great deal from Music Direct on them. Silk dome tweeters (perhaps give a more laid back sound) may be a good match for your NAD. They are 89 dB sensitive, front ported, and best of all comes with a cat friendly fascia.
Here is a review I found.
http://www.epos-loudspeakers.com/wp-content/uploads/2015/01/K2-Hi-Fi-Choice-Web-Quality.pdf