Thats such a loaded question (if you only knew), I am sure you will get lots of great answers, if you want to start, visit the Texas State Parks website at
http://www.tpwd.state.tx.us/
You can "find a park" by area of the state or by faclities Note its one big diverse state. We have been to at least 20 of the state parks and all were good for different reasons.
I know folks like private campgrounds and COE parks too.
Our favorites are Daingerfield in east Texas, Fairfield in central, Caprock Canyons in NW, Davis Mountains in West Brazos Bend South and Inks Lake in central. Need more specifics me know.