I'll break it down:
Our draft choices were Reggie Bush(RB), Vince Young(QB), Matt Linnard(QB), and Mario Williams(DE) in that order.
The Texans sign David Carr to an 8 year extention, so Linnard and Young are out. Linnard never had a chance because if the Texans drafted a QB, it would have been the hometown boy Vince Young.
This leaves Bush and Williams, this is where the draft gets stupid. To everybody who doesn't know the reason why we picked Williams, its simple defenses win championships. The Indiannapolis Colts who where over the cap limit had two choices; keep the RB or DE, they let go of Edgrinn James(RB) to keep one of the DE guys on the team. Because of that the Texan organization picked up Super Mario, who isn't so super right now. We do have a running back named Dominick Davis, he is injured right now but will start the season. He has rushed for more than 1,000 yards for the last 3 years, he is good.
To recap we have a QB and a RB, so we picked up Williams. If it were me I would have picked up Bush.