I'm with FlyingHoustonian.... Much depends on your schedule and lodging in Galveston, where the upscale hotels are not easy to locate or accustomed to late night arrivals. Late night, you're talking about 1 1/2 hours of driving from the car rent counter to the causeway. Morning drive? Quien sabe, but more stress time behind the wheel.

You've 60+ miles of unfamiliar metro between IAH and Galveston, not a complex route, S. on JFK/Airport Drive to Sam Houston Tollway/Beltway 8, W. to IH45, then S. to Galveston (and South of downtown, the Gulf Freeway is lined with hotels, from "Hot Pillow" to recognizable chains). Yes, the late night traffic will be as light as it ever gets, but were it I, I'd simply stay at the airport. I've stayed at the Springhill Suites on JFK - the feeder road to/fm terninals, on several occasions, usually with decent rates, and had no cause to complain.

Don't worry about starting early the next AM. The traffic to downtown builds up early, and unless you're in the car by 6AM, you might as well linger over the free (but unexciting) breakfast, drink coffee and read the paper until 9AM. Houston, N & S, is not the world's worst traffic, but Houstonians, especially those in pickups, drive with reckless abandon on the short stretch of the Beltway, IH45 through downtown, and when IH45 becomes the "Gulf Freeway".

If your schedule in Galveston requires an early arrival anda late night drive, I'd push it as far as the Clear Lake City's motel row (far enough S. to miss the next morning's heavy traffic), or in my case, on across the causeway on to the island, not far. There's a decent Springhill at about 61st St., and unless you've more grandiose hotel plans (and Galveston is not the center of grandiose hostels), the island is small enough for it to be convenient.