I would suggest Dgex, the site looks terrible, but the operator is trustful and you will get your Nxt quicker than with Crypsy. 
http://dgex.com/index.htm?2254 (ref. link)
http://dgex.com/index.htm?2254 (ref. link)
Ugliest site on the net.
I had some money there,but it was so many delays with withdraw,many other upsetting things...
that after all I got all my money from there, step by step-this is VERY HARD JOB TO TAKE YOUR MONEY BACK FROM dgex.com
Now, I do not want to hear anything about this bad smelling site...
Cheers