I'd second Paul's question - where do you want to start? To me, anyway, the more interesting things about Houston are the size (massive) and the different styles of building that are present. I'd recommend starting off one end, working your way around and heading out.
For example, here's an example waypoint list:
* IF COMING IN FROM THE WEST, start at TME (new airport, sort of out in the boonies). Head East and watch the Burbs grow.
* IWS (in the thick of the Katy / West side 'burbs). Follow I-10 East (can't miss it!) and take it to downtown. One of my fav stops in Houston for gas or overnighting.
* IF COMING IN FROM THE N or NW, hit EYQ and continue SE along highway 290, then pick up I-10 east to downtown.
* Downtown @ 1500 AGL. Stay clear of the Class B!
* For the extended tour: Skirt the western edge of the SFC Class B, go near Rice University, past the Galleria area, turn south, check out the Astrodome in the distance, WATCH THE TOWERS and wind up at AXH. Watch the city stretch out but finally tail off and give way to coastal marshes and range land.
* From there, turn to about 110 to hit San Louis Pass (Western end of Galveston) and watch the landscape change. Fly over Galveston and check out the state of the Island. Pass GLS and go to the Bolivar penninsual and check out the devistation. If you've really got time, land at GLS and check out the Island.
* When you've had enough of Galveston, head towards MHF and T41 and check out Galveston bay. Seabrook and Kemah are home to the third largest sailboat fleet in the US. Wave hello to NASA and Paul just on the south end of the EFD Class D. EFD can be an interesting stop, rub elbows with T-38s. Don't be surprised to see Feds in the FBO terminal.
* From T41, work north past the refineries and chemical plants. You will get a LOT of strong thermals from plumes and more than a few funny smells if you're below the mixing layer, which you probably will be, given the Class B starts at 2000 MSL. Use caution for SWA departures from HOU, as they normally egress through this area. Ponder the environmental impact of everyday things like plastic cups - this is where the raw materials are made.
* Check out the San Jacinto Monument. Taller than the Washington Monument, no Texas tale that. Site of the key victory of the Texans over Mexico.
* From there, you can either egress north, avoiding the IAH Class B (very little chance of clearance through there) or take the I-10 corridor back across the city and egress to the west. Either way, head to 11R for lunch (fried catfish and a blue bell malt).
Short tour: TME IWS Downtown T41 GLS MHF VPTNE and your choice of egress.
My other notes from my visits there:
Watch the Class B! It has many funny corners and layers.
Don't expect much help from approach. They are focused on getting commercial traffic in and out of IAH and HOU. If you're lucky, they will give you a code and point out traffic. These guys are really busy and just don't have much time to fool around with us.
Watch for towers. The terrain there is totally flat, meaning that the towers are tall. Several are to 2000 AGL.
Enjoy the trip and welcome to my home town!
TODR