noidiotsplease's review is right on the money, so i'm just amplifying what's already in that write up.
San Marco, like its "sister" shopping district in Avondale, is one of the best JAX shopping and dining destinations for well-heeled locals. Great women's shopping at LUNA (stylish, $$$ casual fashion). 5 Sisters Boutique (eclectic, LA-type clothing--Sue Wong, Parameter, lots of glitz), Beverle's (extension of popular Beach store), Rosie True (quirky--great t-shirts and high-end jeans), San Marco Petites (obvious) and Krista Eberle (clean-lined career and country club dressing, from casual to dressy-a favorite). There are also some designer consignment shops down the road.
Men can shop at Karl's--very high-end American and European designer fashions, and excellent service. Other stores include a good kitchen emporium, a fine used book store, an elegant stationers, an eclectic boutique for French Provincial housewares, an art gallery, a very expensive and elegant Bath and Linens shop, Underwood's Jewelers (most chi-chi in JAX), a good custom carpet store, and, I'm sure, some others that are slipping my mind.
What to buy If you've got the means, grab your platinum card and start spending! And don't miss the adorable (and pricey) children's clothing at Duck Duck Goose. After blowing your paycheck, have a glass of wine at The Grotto, or a latte at Starbuck's with the chocotale-covered popcorn you bought at Peterbrook's Chocolatiers. If you've been there all day, stop in for a movie at the San Marco theater---which also sells pizzas, sandwiches, beer and wine that you can eat at the special little tables next to your theater seat.
What to pay As much as your credit card can tolerate.
San Marco Square, an artsy shopping, dining and entertainment district just south of downtown, is one of Jacksonville's trendiest destinations. Its historic Italian influenced architecture stretches along the Y-shaped intersection of Atlantic and San Marco Boulevards just west of Hendricks. At the center of the Square, a giant statue of three lions watches over Bails Park and its classic white bandstand.
In the Square you can stroll through art galleries, boutiques, independent bookstores and upscale gift shops while trying to decide if you want to dine in class (e.g.: at a two-story Thai bistro and live music club, a sushi bar, an eclectic sidewalk cafe with absolutely fabulous desserts or at an elegant wine grotto) or if you would rather enjoy cheaper treats (e.g.: at a casual, pet-friendly sidewalk pizza parlor, a Chicago-style bar & grill or at a popular local hot subs chain). There's even a chocolate boutique to drool over. Don’t forget to enjoy the latest art film or first run release showing at the old-fashioned art deco San Marco Theatre as well. If live performances are more to your liking, catch the latest production of Florida’s longest running community theatre at the playhouse.
Further exploration of San Marco will uncover numerous other fine dining and trendy casual restaurants, along with nightclubs and day spas. The streets south of the Square are lined with stately old estates and riverfront mansions certainly worth a look. Peterbrooke Chocolates also offers tours of their chocolate factory located on San Marco Ave.
San Marco Square gets very busy during the lunch hour, when executives and yuppies hop over from downtown to grab a bite, and again when they return for a happy hour or dinner. Behind the shops and restaurants lining Atlantic Blvd. is a large parking lot -- good to know in case all of the on-street parking spaces are taken. A free trolley also shuttles people back and forth between downtown and San Marco Square during the day.