I'm not the expert on this either, but,
Jadeveon Clowney , 6',6", 268 lbs South Carolina seems to be top choice some draft boards recommending for Texans
http://fansided.com/2013/12/02/2014-...-takes-1-spot/
The Freshman QB from Florida St might be worth waiting a year for, although not sure he would pass Texans ethics background check..
Right now, my opinion for top three draft picks is all defense, two pass rushers, DE and OLB, then a tall playmaking CB like Seattle has who can cover the tall Wr and TE.
There are a few other top pass rushers in this draft such as Barr from UCLA.