San Antonio. The Alamo, the Riverwalk, the Missions. Then the Hill country with Luckenbach, Fredricksburg, Kerrville, Sisterdale, the Guadalupe river, Highway 16, etc. Especially in the spring when the bluebonnets are in season.
Corpus Christi, Padre Island.
Galveston, Port Aransas, etc.
Deep East Texas around Nacogdoches, Lufkin, and San Augustine.
Disclaimer, I live in the San Antonio area, and love the photographic opportunities.