If you plan on fishing around the hill country rivers or a little farther south for sand bass I'd look for a kayak around the 12' range. You'll want something stable and is more maneuverable to help negotiate rapids and debris. If spending time on a hill country river a kayak on the lighter side is beneficial to help in portaging.
The Bass Pro Ascend kayaks are a good choice. I prefer the 12T
over the 128T
because of price ($650 v $850) and weight (77 lbs v 96 lbs). You lose the hi/lo 360 swivel seat, but it's the trade off I'd make for the cost and weight savings. Plus, even though the 128T is longer you're not gaining any more weight capacity.
Native Watercraft is going to release the Manta Ray 12 XT
sometime this early spring. It looks like a helluva of a kayak for $900. Obviously I haven't paddled it yet, but I really like the lines and think it would make a great all around kayak. My only knock is the 325 lbs weight capacity.
The Perception Pescador Pro 12.0
is proven hull that excels on smaller bodies of waters and rivers. Practically the bar which all entry level kayaks are measured against. Not the best tracking of this group, but it has a decent weight capacity of 375 lbs and is light weight compared to most kayaks. It drafts shallow too, which is nice for rivers.
The Vibe Sea Ghost 130
is another all around kayak that will handle bay fishing to small Hill country rivers. It's a China made kayak, but you do get a lot of kayak for the money; including a rudder. It has a ton of weight capacity at 550 lbs.
Two other kayaks which may be harder to find in Texas but look like great fishing platforms are the Emotion Stealth Pro
(Cableas should carry it) and the Crescent Light Tackle
. The Emotion is on the heavy side, but it does have a little more weight capacity than the Ascend. I don't know much about the Crescent, but I like th elines and it has great weight capacity at 500 lbs.
FYI, if you add a trolling motor to your kayak you'll have to register it with TPWD.