I've own a villa in Venice, which is about 20 minutes south of Sarasota on the Gulf, for 10 years or so. I think the suggestions doing your due diligence is definitely warranted. The new construction is or wasn't inexpensive to purchase and tends to be inland from the beach. A lot of the older homes/condo's/villas are located nearer the beach, shopping and the downtown area and were constructed in the 70's so most need up-grading. For many reasons I think this is the way to go. Buying older gets you a better location and once done the renovations, you know exactly what you've put into the place from a quality stand point. Labor tends to be reasonable, but I'm used to paying NY-NJ prices.
The Venice area is an older community and I highly recommend it for several reasons. The biggest being they have not been hit by a hurricane; ever. The native population prior to the 18th century used the area as a safe haven from bad weather. Not to say we don't get storms, high winds, etc, but nothing like what the East Coast gets or even south of Port Charlotte and south or above Tampa.
That said, it's no South Beach and the architecture is nothing to write a book about. The island does have quite a few spanish infulenced buildings both public & private. It tends to be quiet and you need to go to Sarasota or Tampa for cultural events, sports or night life. Although there are some some local places in downtown Venice and the surrounding area that are terrific fun for a night out and a good value for the buck. Boating and fishing are all around you as the inetrcoastal divides the town of Venice from Venice main land. There is a small airport in South Venice that caters to a strong European influx of vacationers. So when you're out on the beach or shopping you'll hear quite a few different languages being spoken. Most housing has come down about 40% from what it was 18 months ago and seems to have leveled out. A lot of this situation was due to over building and the inventory is starting to move. Real-estate predictions seem to be saying things are starting to come back and they are expecting a decent 08-09 season. Remains to be seen. For more info here is a decent site to start:
http://venice-fla.com. Venice is a well kept secret.
Happy shopping!