Over the counter Lindt is amazing and readily available. I usually go for the dark orange or dark mint bar.
Next in line for me is Vosges.
http://www.vosgeschocolate.com/
They make some of the most interesting bars out there. They have a great Black Pearl bar that has Wasabi and ginger in it which is out of the world.
Boutique chocolates I have to go with Chocolate Bar NYC
http://www.chocolatebarnyc.com/
Granted this is my fucked up Ex's store but her quality and attention to detail on the bars is amazing. I still send interns there to get me the dark chocolate NYC pretzel bar.
Yes, I eat alot of chocolate... and these are my recomendations...