sorry, I tend to drink whenever and not just for the happy hour. that said, the Chart Room (300 Chartres) is always lively and has good prices. cold beer and terrific bloody mary's.
my other haunts are Harry's Bar, Claire's Bar, Touche', Carousel Bar, and French 75 at Arnaud's.
recently opened on Decatur is Felipe's which does some happy hour specials w/ drinks and food.
you might also consider going to Vieux Carre Wine & Spirits and share a bottle or two at the shop or while walking/shopping.
years ago, Fridays were good at House of Blues Courtyard Bar. don't know about that scene right now though.
you also can't beat Napoleon House and Lafitte's Blacksmith for history and atmosphere.
I love Coop's on a rainy afternoon looking out the window and watching life go by. same for Napoleon House sitting just off the sidewalk.
for view, go to the rooftop of the Royal Orleans at sunset for poolside drinks.
I like champagne and oysters at Bourbon House or Desire Oyster Bar.
geez, I'm making myself thirsty. gotta go chill something now!