Mark,
NOLA is my favorite city in the US. So much to see and do, really hard to set an itinerary.
Records Stores:
Euclid Records
Louisiana Music Factory
Peaches Records
Skully's
To name a few.
Music Venues:
Preservation Hall
The Spotted Cat Music Club
Maple Leaf Bar
Blue Nile
There are SO many music places to see and hear, that you could spend weeks and not see all of them.
For a REALLY cool and different thing to do, if you're there on a Friday or Saturday night, go to the midnight showing of the "Rocky Horror Picture Show" at the Prytania Theatre.