While I'm not crazy about what I've seen from Reeves so far (and what I heard about him in Dallas), I don't think there is much dispute that the Texans had to bring in some veteran to play CB. Dunta was (and somewhat still is) a complete unknown. What we've seen from Bennett is encouraging but by no means a sure thing yet. Although we all expected the Texans to draft a corner, it was unknown who would be available (and it appears as though the Texans were targeting left tackle in the first round) so you couldn't count on this. Thus, they clearly needed depth at that position and were going to sign a free agent. If we're going to debate this signing, I think it should be done in the context of who was actually available.
Here is a list of this year's CB free agents -
http://www.walterfootball.com/free2008CB.php
Based upon what it would cost to sign them, who would you rather have?