Where will you be in Houston? There is great bayou fishing near the city if you don't want to travel far. I have caught alligator gar, largemouth, channel cats, blue cats, bowfin (my personal favorite), carp, bluegill, crappie, and buffalo on the fly all within 5 minutes from my house. Carp are some of the hardest fighting fish I have ever encountered and they can often be found cruising or tailing in clear water which makes for some insane sight casting. Better bring a minimum 6 weight for those bruisers, and be prepared to see your backing, I have fought a 5 pound carp on an 8 weight for over 30 minutes.
Here are a few pictures of some city fish.
http://www.texaskayakfisherman.com/forum/v...ic.php?p=866887
http://www.texaskayakfisherman.com/forum/v...ghlight=#815856
Texas has a huge variety of fly fishing challenges and their is something for everyone here, from redfish in the flats, to smallies in the pristine devils river, to huge LMBs in lake fork. The Guadalupe river in the hill country was even rated one of the top 100 trout streams in America!
Here are some cool websites about fly fishing in texas
http://www.flyfisherman.com/south/sstexas/
http://www.expedition-outfitters.net/index.html
PM me if you want more info or anything, I love the whole warmwater fly fishing thing and would be happy to give you some tips.
I apologize for the rant, I just love texas fly fishing!