You'd be surprised how often it rains in Florida. And I really hate to ruin the potential befuddlement, but be prepared for crazy 5-minute, downpours in the summer...all while the sun is still shining. Of course we have plenty of occassions when it's just dark and lighting and thunder rain down with all the water; Florida is the lighting capital of the (I wanna say world, but maybe just the US).
I-4... You may or may not be better off taking the long route on the regular streets to get around. The toll roads are very brisk...but they're toll roads.
I'm not the bar-hopping/clubbing type, but it seems that in the three years I've lived here, that's the "best" part of downtown. If you're into live music and concerts, Orlando is an awesome town to catch a show, both in small club-type venues and the bigger House of Blues and Hard Rock Live. Oddly, though, we don't get too many of the arena tours; those seem to wind up in Tampa instead (something like an hour/hour-and-a-halfish drive).
Orlando is in the center of Florida, so you'll actually have to drive a bit to get to a beach. They say you're never more than 50 miles from the coast at any point in Florida, and that's actually how far you'll have to drive.
City life... I haven't lived/spent much time in cities. I think everything worth seeing downtown is central, which is good because apparently our public transportation sucks.
Unless you've got friends/relatives from out of town always visiting you, you'll be surprised how little you'll be going to the theme parks.
I live right on the northern edge of Orlando in the UCF area and only really venture into the city for concerts. The toll roads can zoom me there in 10 minutes, whereas taking the "main road" into town can take upwards of half an hour, traffic non-withstanding.
