2.0 Stereo speakers on a $2000 budget?

Custom makers will build you incredible speakers for that amount. :)

Are you looking for floor standers or bookshelf or standmounts?

If you are located within driving distance of southern California, there is a  pair of awesome VMPS RM30 speakers with auricaps, silver wiring, side 10" woofer, two 6" woofers, two 6" passive radiators, 3 neoribbon midranges, and a FST ribbon tweeter per speaker.  They need to be picked up--110 lbs. each.  There is a picture and description on p.36 of Audio Circle--VMPS speakers.  The seller was a demonstrator and seller of their speakers.  I was also and owned a pair of these.  I still have their big brother RM40 in a very nice system.  If John still has them for sale and they aren't bought yet, it would be hard to beat these at his $1500 asking price.  There are a couple of reviews you can read online.  These were about $5300 new--dynamics, clarity, soundstage, good clear bass, and adjustability to any room or system in the mids, highs, and bass.  At $5300 they were a steal.  If you don't live close enough, that's too bad.  I friend who bought a similar pair from me uses a Japanese theater amp and a cheap cd player and swears they sound stunningly good.  They sure did in my system--the 40's have deeper bass, can play a little louder, and a slightly higher soundstage.

I would go with a pair of Vandersteen Model 1's. You can put them next to anything you want up to 2k. Over the years, I've compared them to at least 30 different speakers, and have yet to hear something that I would say sounds better for anything near what they cost.

Your room is big enough for a pair of planars, if your taste includes them. Many would suggest the Maggie 1.7i, but even better is the Eminent Technology LFT-8b, a hybrid magnetic-planar/dynamic woofer design. Easier to drive than the 1.7i, too. $2499 retail, rarely found second hand.

My thinking, given that you own the NAD 356 integrated and CD player and want to keep them. 

There are many choices that would mate well with this amp and represent a major upgrade from your aforementioned speakers. I totally agree regarding the Klipsch RP-160M. I have a pair which I drive with a NAD 326.  

I generally don't get into recommending speakers as choice is so subjective, however I agree with the Vandersteen recommendation as one to consider. Given your room size I would think the 2C to be the better choice over the 1C. The new version of the Vandersteen 2Cs retain at $2200 I believe. Earlier versions come up used and can be had for much less. They are very highly regarded and can be driven effectively by your amp (80wpc). Should you wish to one day, they will respond to an upgrade in amplification. Look them up, call Richard regarding questions.