Any rig dive is nice....
plus, the Rigs to Reefs program is going along nicely. Most dive shops can provide you with charters to these sites. NOAA can provide provide private boaters with Lat/Lon coordinates.
Inland dives....
Lake Travis... 20-100'+Wrecks, submerged forest, lots of neat stuff....(almost anywhere is nice when the water is clear). Also great for nekkid co-ed watching, not that I do that....
Canyon Lake...20-100'+...about the same as Travis. Fewer nekkid co-eds.
Toledo Bend 10-70'+ (tannic acid in water, so it's spooky deep. But the water can be relatively clear, if dark below 40'). Submerged bridges and roads. No nekkid co-eds. Some nekkid Coonasses, but that might be too much information....
San Marcos River...3'-20'. very shallow, but very clear drift dive. You can see the rare, endangered San Marcos Prawn, which travels to the gulf for breeding. There are lots of Koi and such dumped by residents........drunk nekkid co-eds (and their drunken boyfriends) often drop watches, Varnet sungless and money as they flip over the falls in their inner tubes, so Sunday evenings are often a great time to "treasure hunt".
Comal River...3'-30'. Same as the San Marcos. Just don't "winter dive it after a flood" like I did....the chutes (spillways) are an E Ticket ride, but pretty scary to do headfirst in SCUBA. Plus, if you miss the last ladder out of the river, you end up in the Guadaloupe River, which is NOT fun during flood stage (I still have scars). I would mention the nekkid coeds, but you guys might think I was obsessing......I'll stop here and simply note that nekkid coeds are a common summer occurence at inland Texas dive sites.
Blue Lagoon. 10-25'. Some funny shrimp, very alkaline water, so no fish. A couple of wrecks and some platforms. A good place to practice and collect dive gear off the bottom (which I return, if I can find the owner, btw.). Notice I mentioned no nekkidness.
Twin Lakes? I haven't been there, but plan to soon. Are there any nekkid coeds there?
oh, and I haven't been to Balmorrhea, the Silos, Jacobs well or Aquarena (sp?) Springs, but I hear they are great. (Excepting Balmorrhea, these require special permission or training.).
Any other spots?