Best solid state amp upgrade from NAD 214?

Emotiva XPA-2. Factory direct for $800.
I simply can't imagine doing any better for the price.
My friend has one it it competes with my much pricier Monarchy amps. Tons of power... very detailed, musical and well made. Runs his Maggie speakers barely getting warm.

There's also a Classe CP-35 preamp with remote posted for $895.
These two pieces would be a big step up from the NAD gear and under your budget.

Thanks for your comments. I'll check both of them out

I personally like using SS amp with a tube preamp.
For a tube preamp check out -
* Belles 21A Auricap Linestage preamp at $1,200,
* Primaluna Prologue Three preamp at $1,100,
* Eastern Electric Minimax preamp at $700
The first two preamps put you at the limit of your budget BUT you have a heck of a pre/amp combo. The last preamp is still a nice choice for less money. I do not have access to Blue Book prices so you'd need to to confirm fair market price for the preamps.
My friend runs a tube preamp into his Emotiva. Makes for a nice combination and a bit more musical versus the two other SS preamps he tried.

You could also get an int. amp such as a Marantz 8004, NAD C275, Yamaha S2000, TEAC. I'd personally change out the pre-amp first and keep the amp. Perhaps try a used NAD C160/162 (used around $300) to match your NAD amp. You might really enjoy the convenience of a remote control. You have a nice amp, w/a few little modifications you would be very surprised how you could really improve the sound. If you really have the urge to change amps, check out the Parasounds as well. Good Luck!