We're considering a March or April '04 trip to NOLA, but don't want to hit a busy weekend. Can anyone steer me away from the big events and conventions? Also, which day is the '04 St. Pat's parade?

Bonn-
St. Pat's is Wednesday March 17 so the major parades and festivities will likely be the weekend of March 13-14.
French Quarter Festival is a variable April weekend - not big crowds at all, and actually a very fun celebration of music and food that draws people locally and from the drive-in regions. It has a website - do a Google search to check the 2004 dates.
Last weekend of April and first weekend of May is the NO Jazz & Heritage Festival - if you don't want to attend this wonderful music festival you'd do best to plan around it. The city is flooded with visitors - restaurants are crowded, room rates are high, music clubs are jammed.
Easter is April 11 - that weekend might be an excellent bet because so few events are planned that weekend. But if you want to go out to eat that day, make reservations now.

The St. Patrick's Day celebrations in New Orleans are not the pandemonium that Mardi Gras is. I don't think too many out-of-towners come for them. There are at least two parades. The smaller one in the Irish Channel is loads of fun and unlike any other. First there are the strutting tuxedoed marchers who pass out paper flowers in exchange for kisses. There are local politcos and beauty queens in convertibles tossing beads and doubloons, and then the tacky floats. You are guaranteed to catch all the cabbage and potatoes you want. Naturally there is good music.

I also love St. Joseph's Day on the 19th. On that day and the one or two before you can visit beautiful and elaborate altars in people's homes as well as churches. They are labors of love (a Sicilian tradition) and can be very moving. They are listed in a special column in the Times Picayune. St. Joseph's church has a fabulous one at the Piazza D'Italia. There is a small parade by the Italian-American community with an altar at the start. The famous Mardi Gras Indians come out then too, in their handmade beaded and feathered outfits, but they can be hard to find.

French Quarter Festival is rapidly becoming one of the "big" events. I'm not sure I'd agree that it has "not big crowds" as we could barely MOVE last year in some parts of the Quarter!

I've been to New Orleans at various times of year. I haven't been during Mardi Gras; New Year's is the busiest time I have seen. The only time the streets aren't fairly crowded is 6-8 am, any time of year. I love getting up and walking the quarter while the sidewalks get hosed down first thing in the morning.