This is a very good question going into this season, with a lot of possible answers.
1) Connor Barwin - Should be the popular pick, because he plays the SOLB position. The position that rushes the QB the most in Wade's defense, not to mention he lead the team in sacks last season.
2) JJ Watt - Another excellent pick, as he really picked up his game towards the end of the season... and really made a name for himself. IMO, he's the most talented player in our front 7.
3) Brooks Reed - He's a bit raw and started sooner than the Texans hoped. But towards the end of the season, especially in the playoffs, he started to really pick it up. With Barwin and Watt getting all of the attention, he'll be the guy there to clean up.
4) Whitney Mercilus - They drafted him too high to sit on the bench, but I really don't know where they'll play him? He's a gifted pass rusher with a relentless motor. If Brooks struggles early, I can see Mercilus becoming the starter. I trust Wade will somehow find a way to get him on the field.
Then there's Cush and Antonio, but I expect them to have a 5-6 sack season.
IMO, I see it going down to Barwin having the most sacks at the end of the season, followed by Watt, Mercilus, then Brooks.