Here's my philosophy - and I'm sure you can tear it apart!
The 4 highest paid positions in the NFL are QB, CB, DE and LT. When you draft a player in the first round, you get a longer term contract and that player will be guaranteed to be on your team for a longer period of time.
So if you have a need at one of these 4 positions, I think it is best to grab them then than at any other time. And I would contend that we have needs at all of those positions other than CB.
Would I thow a fit if we drafted a DT? Nah. But I'd be more excited if it was a top notch DE than a DT. JMO.